Monday, February 27, 2012

Witticisms in the Face of Mass Extinction

I fear that this posting will be taken as a retelling of an old joke or several jokes from paleontology.  That’s one advantage of being a paleontological amateur of recent standing, these are new to me.  Actually, the term “jokes” misses the mark, these are “witticisms” fashioned by clever paleontologists to describe real phenomena.  I found these all at once, rather than spread out over the decade in which they came into being.  That timing may explain some of my unease about this cluster of witticisms, the focus of this posting.
Earlier this week I spent a dreary morning in the Library of Congress’ Science and Business Reading Room.  The weather outside offered lowering clouds that threatened rain, and a building wind.  This complemented the atmosphere inside with its dim lights, dark wood desks, and a sepulchral echo whenever someone dared to walk the aisles.  All totally appropriate for the texts that lay on my desk, texts recently released from the bowels of the library.  The books were not old themselves – none of the volumes on my desk dated from earlier than the mid-1980s, but the tales they told were ancient – tales of mass extinctions.

(Given these atmospherics, this moment in the drafting of this posting constitutes a fork in the road.  In one direction lies the story I intend to tell, a relatively light-hearted one with a bit of my curmudgeonly attitude attached to it.  In the other direction floats a “ghost” story, perhaps something involving a dusty volume with engravings from which spring long extinct creatures.  Say, for instance, a rash of trilobites breaking the quiet with their skittering across the desks as they flee from the plate volume of Reverend William Buckland’s Geology and Mineralogy Considered with Reference to Natural Theology (1837).

Ah, that would be a ghost story inspired by those magical texts conjured up by Montague (“Monty”) Rhodes James a century ago (such as those he published in Ghost Stories of an Antiquary, 1904).  James, of King's College, Cambridge, wrote ghost stories in the British tradition, stories laced with horror and the macabre, not ghosts, per se.  Part of the horror of my tale would be the prospect of other extinct creatures sliding or thundering from the engravings.  Perhaps some other time, there are paleontological witticisms to explore first.)

Those who study mass extinction events distinguish them from background extinction, that continuous process of winnowing taxa (taxonomic groups), a sort of white noise of extinction.  In contrast, mass extinctions, according to paleontologist Peter D. Ward, “are geologically short intervals of intense species death.”  He notes that, “During the last 530 million years of earth history, the time since the advent of commonly skeletonized creatures on earth, there have been about 15 mass extinctions.  Five of these may have involved as many as 50 percent of the earth’s species.”  He considers three of these to be “major” because they “completely reorganized the ecosystems in the sea and, more relevant to humanity, on land.”  These would be those of the End-Permian (truly, the mother of all extinctions), Late Triassic, and End-Cretaceous.  (Rivers in Time:  The Search for Clues to Earth’s Mass Extinctions, 2000, p. 6.)

It was a morning of contrasts in the LC reading room.  For all of the death that marked mass extinctions and the profound impact these events had on earth’s living organisms, mine, though, was mostly a light-hearted charge.  Critical to analysis of extinction in general, and mass extinction in particular, is determining whether a taxon or taxa have in fact gone extinct.  It’s no simple exercise.  I had been struck by how thoughtful paleontologists have been in identifying the subtle processes that might affect that determination in the fossil record.  Equally striking, though, is how analyses of these situations prompted several paleontologists to engage in clever wordplay to capture their essence, wordplay that, in my mind, may challenge the usual gravitas of the science.  That was my pursuit – the origins of several of the best of those scientific witticisms.  It was really nothing new, very well-trod ground.

Here then are the three bits of wordplay that I explored.

Lazarus Effect

In the early 1980s, paleontologist David Jablonski demonstrated his familiarity with the New Testament when he gave a name to the phenomenon of taxa that disappear from the fossil record in mass extinction intervals only to resurface some time later, apparently not victims, but survivors.  “This disappearance and apparent extinction of taxa that later reappear unscathed can be termed the Lazarus effect.”  (Causes and Consequences of Mass Extinctions:  A Comparative Approach, in Dynamics of Extinction, edited by David K. Elliott, 1986, p. 197.)

It’s a clever and memorable label for such an occurrence.  Perhaps, he suggests, these Lazarus taxa sought refuge elsewhere, riding out the storm, so to speak.

I don’t intend to demean this first term, which I think is a stroke of genius, or the phenomenon it describes.  The Lazarus effect is not just a curiosity.  Jablonski uses it to great advantage, seeing it as “a rough indication of the completeness of the fossil record for the interval in question. . . .  The magnitude of the Lazarus effect is an indication of the distortion suffered by the fossil record in that time interval.”  (p. 197)  Further, “the Lazarus effect, can be used to assess patterns of extinction near mass extinction boundaries:  apparent gradual declines in taxonomic diversity leading to the extinction event can only be accepted as genuine if they exceed the magnitude of the Lazarus effect.”  (p. 211)

Elvis Taxa

In a 1993 piece, paleontologists Douglas H. Erwin and Mary L. Droser consider a related issue – the accurate identification of Lazarus taxa.  (Elvis Taxa, Palaios, Volume 8, Number 6, December, 1993, p. 623-624.)

They acknowledge the importance of the Lazarus effect for its utility in characterizing the quality of the fossil record, and, based on the length of time between the disappearance and reappearance of the Lazarus taxa, its contribution to an understanding of some aspect of the recovery of the environment after the extinction event.  But they stress that its usefulness depends upon correctly identifying the Lazarus taxa.  They note, “Extensive homoplasy and morphologic simplicity may confound recognition of Lazarus taxa.”

As I understand it, homoplasy describes the situation where unrelated taxa share very similar or identical morphological traits.  (See, for example, Homoplasy, A Good Thread to Pull to Understand the Evolutionary Ball of Yarn, ScienceDaily, February 24, 2011.)  As a result, finding such a taxon may lead to the conclusion that its look-alike had risen from the grave when it hadn’t.  “These apparent Lazarus taxa are a taxonomic artifact.”  Erwin and Droser “suggest that such [ersatz Lazarus] taxa should be known as Elvis taxa, in recognition of the many Elvis impersonators who have appeared since the death of The King.”

They then argue for the positive contribution of such taxa for our understanding of possible limits to the amount of “play” in evolution.
Elvis taxa, properly recognized, illustrate the pervasiveness of homoplasy but also the constraints on morphological evolution and community construction.  If Elvis taxa are as common as Lazarus taxa they may indicate that morphology may be more highly constrained than commonly believed, or that particular roles require particular morphologies.
I have to admit that this particular label strikes me as a bit too playful.  Even Erwin and Droser appear to be sensitive on this score.  They acknowledge,
New terms should be proposed with caution, when they describe a particularly important phenomenon, and never in jest.  In addition, terms should be short and memorable if they are to achieve any currency.
Hmmm, . . . Elvis taxa . . . memorable, sure, but I have to think these two paleontologists had a laugh, or several, when they coined the name.  They explicitly reject following in Jablonski’s biblical footsteps, aspiring to what they characterize as “a more topical approach.”

Zombie Effect

In Dinosaur Extinction and the End of an Era:  What the Fossils Say (1996), paleontologist J. David Archibald waxes enthusiastic about the fossil record despite its limitations.
The spotty nature of the geological record is not unique to natural history.  All histories bear this burden.  There is, however, no cause for despair.  The information that has been preserved in the rock and retrieved by human effort is truly a wondrous précis of past life. (p. 64)
But he strikes a serious cautionary note, “The difficulty comes when we must determine whether our record is accurately portraying the biological past.”  (p. 64)

He focuses his concern for the accuracy of the record on the implications of several different phenomena, including the Lazarus effect.  He introduces a new term, the Zombie effect, for a potentially misleading artifact of the fossil record resulting from the reworking of fossils from older rocks to younger ones, leading to the erroneous conclusion that some taxon was alive after it had actually gone extinct.  These reworked fossils, Archibald writes, “lurk in later sediments like the living dead.”  (p. 68)

He describes organic (e.g., burrowing) and mechanical (e.g., changes in streams) processes leading to the Zombie effect.  And then reinforces his initial cautionary warning,
I argue that the Zombie effect is far more common that we paleontologists would like to believe.  Basically, we should be suspect of any fossil bone that is not articulated with a good bit of the rest of the skeleton.  (p. 70)
Surely Archibald has fun with this term, making sure he works in phrases like “the living dead” and “exhumed remains of organisms that lived earlier” to describe the Zombie effect.  I suppose once the literature sports terms like Lazarus effect and Elvis taxa, Zombie effect doesn’t seem so far out of line.

Still, even though I particularly like the Lazarus effect (I suspect it was not offered in jest), I would suggest that these very real, very important phenomena are somewhat devalued and robbed of some their deserved gravitas by the cumulative effect of these witticisms.  Restraint is in order.  But, after reading a column by Edward Willett (Guess How Some Fossils Are a Lot Like Elvis, Regina Leader-Post, February 1, 2007), I have to wonder whether that's possible.  Some two decades after Archibald brought forth the Zombie Effect, Willett mentions that some would describe “so-far-undiscovered bones that must be hidden somewhere” as a Jimmy Hoffa taxon.  May it stay buried.

Perhaps this turned out to be a ghost story after all.

Monday, February 13, 2012

In Search of John Smith and the Calvert Cliffs

The river is within us, the sea is all about us;
The sea is the land’s edge also, the granite
Into which it reaches, the beaches where it tosses
Its hints of earlier and other creation:
. . .
The sea has many voices,
Many gods and many voices.
                            ~ T.S. Eliot, from The Dry Salvages in the Four Quartets

I spent a recent winter morning wandering the beach below a stretch of the Calvert Cliffs.  The Cliffs are a remarkable geological phenomenon.  From sediment laid down periodically in a period from roughly 18 to 8 million years (a sizeable chunk of the Miocene Epoch), the Cliffs run south for 30 miles on the western side of the Chesapeake Bay, from Fair Haven to the mouth of Patuxent River.  In places they soar to over 100 feet.    The oldest formation (the Calvert) is exposed only at the northern end and it was there that I was in search of Miocene mollusks, particularly gastropods.

To be frank, that’s a foolish thing to do (setting my sights on a specific kind of fossil) when the hunting venue consists of the “float” along the shore, where the waves play randomly with fossils that have eroded from the Cliffs.  It’s better to go with no expectations and be on the journey just for the hell of it.  My gastropod finds were minimal, although the array of marine invertebrate and vertebrate fossils that I picked from the cold water reflected, in a very small way, the rich diversity of the Miocene fauna in this area which, by one estimate, includes more than 600 species.  I’m still determining the identities of the fossils that I found that day, a process to write about later.

Ultimately, I think, the best find of the day will turn out to have been a feeling, one that came to me as I paused in my hunt and looked east across the water.  At that moment, I was alone on the beach and saw no boats on the Bay.  The only sounds were the sporadic rustle marking the fall of bits of sand from the cliff face, and the slap of waves on the shore accompanied by gurgles as water filled and emptied holes in exposed clay (where mollusk fossils had once been).  For a moment, four hundred years slipped away and I sensed how these Cliffs might have appeared to a certain 17th century explorer who ventured up these waters, in sight of these Cliffs, and who encountered (frequently for the worse) many of the Native American communities on the lands that bordered the Bay.  Admittedly, it’s not all surprising that in these circumstances my thoughts turned to Captain John Smith, “sometime President of Virginia” and “Admiral of New England,” because his words appear in several of the texts I’ve read on the geology or paleontology of the Calvert Cliffs.  Well, his purported words.

This calling on me by the spirit of John Smith is not a new experience along this shore.  One fall day, about three years ago, I was fixed by the sight of a vessel with brilliantly white sails set on two or maybe three masts.  I managed to capture one poor image on my cell phone of this “ghost ship.”  The intervening centuries disappeared that time, too, and Smith’s spirit was upon me.

I’d never turned to the primary sources in search of Smith’s words about the Bay and the Cliffs, but after my most recent outing I went on a hunt in the pages of texts first published in the early years of the 1600s.  A tangled literary thicket surrounds John Smith.  What did he actually write?  What did other hands do to his original words?  What might have he contributed to works not attributed to him?  Which texts are ascribed to him but shouldn’t be?  Trained as an historian, I shouldn’t have been surprised by this challenge regarding a 17th century writer, but I found cutting through this thorny mess to be hard, frustrating work, as challenging as identifying an unknown fossil or untying the taxonomic knot of the scientific name of some species.

After much floundering, I came to rely on the Smith texts contained in Narratives of Early Virginia 1606 – 1625, edited by Lyon Gardiner Tyler, 1907.  (Unless otherwise noted, any material quoted in this blog posting comes from this book.)  I also worked with the “digital copy” of Volume 1 of The Complete Works of Captain John Smith (1580 – 1631) in Three Volumes, edited by Philip J. Barbour, 1986, as presented on the Virtual Jamestown website, a collaborative project involving Virginia Tech, the University of Virginia, and the Virginia Center for Digital History at UVA.  Barbour’s analysis of the authorship of the various pieces helped immeasurably.

My first introduction to this penchant for quoting John Smith when addressing the geological or paleontological nature of the Calvert Cliffs had come in Wallace L. Ashby’s Fossils of Calvert Cliffs (1979).  After acknowledging that, in 1588, the Spaniard Vincente Gonzalez might have been the first European to see the Cliffs, Ashby wrote
Captain John Smith, during his exploration of the Chesapeake Bay in 1608, described the cliffs as “. . . mountains of diverse nature, Marle, Fullers earth . . .”
I am wary of ellipses (inserted or omitted).  As will become clear, the text just quoted is an example of their damaging effect.  (Excerpting T.S. Eliot with ellipses, as I did at the top of this posting, is fraught with danger as well.)

At the outset, I would observe that these words of Smith’s are not from the narrative of his exploration of the Bay in 1608.  Rather, Ashby drew from what is perhaps the more geologically intriguing piece that might have some bearing on the Cliffs, at least in part.  It is probably in Smith’s own words, appearing in his A Map of Virginia With a Description of the Countrey, The Commodities, People, Government and Religion, (printed in 1612).  In it he described Virginia, including the Bay, without specific reference to his Bay explorations of 1608.  More on those in a moment.  First, I need to unpack what Ashby crammed together and misconstrued.

In his description of Virginia, Smith noted (for all of these quotations I have left the spelling as I found it in Narratives of Early Virginia), “There is but one entraunce by sea into this country, and that is at the mouth of a very goodly Bay, the widenesse whereof is neare 18. or 20. miles.”  (p. 81)  In describing this north – south lying Bay, he observed that at its head are mountains which stretch in a southwestward line.  As a result, “the more Southward, the farther of[f] from the Bay are those mounetaines.”  (p. 82)  Keep in mind the orientation of the mountains – they are more and more removed from the Bay as one journeys south along its western shore.

In the full passage that Ashby mangled (taking the first phrase of the paragraph and smashing it into text buried deep in the paragraph), Smith wrote,
The mountaines are of diverse natures, for at the head of the Bay the rockes are of a composition like miln-stones.  Some of marble, &c.  And many peeces of christall we found as throwne downe by water from the mountaines.  For in winter these mountaines are covered with much snow, and when it dissolveth the waters fall with such violence, that it causeth great inundations in the narrow valleyes which yet is scarce perceived being once in the rivers.  These waters wash from the rocks such glistering tinctures that the ground in some places seemeth as guilded, where both the rocks and the earth are so splendent to behold, that better judgements than ours might have beene perswaded, they contained more then probabilities.  The vesture of the earth in most places doeth manifestly prove the nature of the soile to be lusty and very rich.  The coulor of the earth we found in diverse places, resembleth bole Armoniac, terra sigillata ad lemnia, Fullers earth, marle, and divers other such appearances.  But generally for the most part the earth is a black sandy mould, in some places a fat slimy clay, in other places a very barren gravell.  But the best ground is knowne by the vesture it beareth, as by the greatnesse of trees or abundance of weedes, &c.  (p. 82-83)
The terms – bole Armoniac, terra sigillata ad lemnia, and Fullers earth – connote different kinds of clayey rock or soil.  Marl (as it’s now spelled) is mudstone.  All of these terms would apply to sedimentary rock.  With the exception of the mudstone, this is some of what Smith certainly would have found along the Bay’s shorelines and come upon in spades at the Cliffs.

Though Smith may well have captured significant aspects of the geological appearance of the land bordering the Bay, I am certain that in this passage he was not describing the Calvert Cliffs specifically.  The “mountaines” that begin the description are not the Cliffs which, in contrast to the structures described by Smith, don’t move away from the Bay as one goes south, but rather rise to greater heights on the shoreline (at least until one reaches the Patuxent River).  He was describing, instead, the actual mountainous terrain that runs from the northeast to the southwest along the east coast of the United States.  It is the snows on those mountains that he commented on and the erosion from their slopes that make much of the sedimentary rock he described.

The Maryland Geological Survey, in its 1906 treatise The Pliocene and Pleistocene Deposits of Maryland, by George Burbank Shattuck did a better job than Ashby, quoting the entire passage and, better yet, not asserting that its words described the Cliffs.  Shattuck observed, “With these meager notes which were not published until 1612-14, Smith summarized practically all he had to say of the geology of the region . . . .”  (p. 25)

Where the Survey’s treatment of the English explorer went astray was in its effort to link these words explicitly to Smith’s Bay explorations in the summer of 1608.  Yes, those are the journeys during which he undoubtedly saw and learned about the geography and geology of the Bay, but these words do not come from a “narrative” of these explorations.  Rather, as I’ve noted, they are part of his description of Virginia which accompanied Smith’s map of this land and its waters.  A view of the complete map appears below with a blow-up of the Bay portion.

The initial image of the map was downloaded from the Library of Congress' American Memory 

What about the narrative of the voyages around the Bay that year, 1608?  The first iteration of such a narrative appeared in The Proceedings of the English Colonie in Virginia (1612) which was printed independently but constituted the “Second Part” of A Map of Virginia.  Chapter V of the Proceedings described the voyage that began June 12, 1608, and Chapter VI described the second exploration of the Bay undertaken later that summer.  I find it interesting that secondary sources providing an account of those journeys routinely attribute the text of these descriptions solely to Smith.  In fact, the Proceedings themselves, though typically included in compilations of works by John Smith, ascribed these chapters to specific other authors, men who accompanied Smith on these trips.  Chapter V, titled “The accidents that happened in the Discoverie of the bay,” recounted the June to July adventure, concluding with this statement, “Written by Walter Russell and Anas Todkill.”  (p. 115)

What am I to make of the Proceedings as a whole, this chapter, and this attribution of authorship?  Philip Barbour called the Proceedings “an often uneven, unclear compilation of accounts of what happened to the settlers of the first permanent English colony on the western side of the Atlantic.”  (The Complete Works of Captain John Smith, volume 1.)  Significantly, Barbour posited,
With regard to the question of the extent to which Smith himself contributed to the accounts included in the Proceedings, there are details that he must have supplied here and there.  There are other details that he could not have provided, though he may well have added personal touches.
The portions that Barbour believed reflected a significant contribution from Smith did not include Chapters V or VI.  He commented, “That Walter Russell and Anas Todkill produced the material for Chapter 5 would not be surprising.  Both of them went on the expedition therein described.  By the same token, the combination of Nathaniel Powell and Anas Todkill is entirely logical for Chapter 6.”

As a result, I doubt we’re hearing Smith’s voice in Chapter V, but I wonder whose we’re actually hearing.  It’s a deftly told account with a striking sense of humor, something hard to achieve, I think, in a collaborative document.  Regardless, it began with the departure from the Jamestown colony (“James Towne”) on June 12th and ended with the return to the colony on July 21st.  Smith and a contingent of 14 men, among them doctor Walter Russell and soldier Anas Todkill, sailed down the James River in “an open barge of two tunnes burden.”  (Elsewhere this weight is raised to three tons.)

The “ghost ship” I’d spied three years ago was certainly not Smith’s because the “barge” on which he went forward into the Bay had only two small sails and was often rowed.  There was no “below deck,” because there was no deck, only a tarp stretched from side to side to offer shelter from the elements.  Writer Terence Smith characterized Smith’s vessel as
an ungainly 30-foot boat called a shallop.  It had been built in England and shipped across the Atlantic in two sections in the hold of a larger ship.  It was strong and heavy (a replica built for the 400th anniversary celebration weighs 5,000 pounds), powered by ten-foot oars or two sails, and steered by a big wooden rudder – in short, a clunker of the first order.  (Beyond Jamestown, Smithsonian Magazine, May 2007.)
(See also The Virginia Adventure:  Roanoke to James Towne, by Ivor Noël Hume, 1994, p. 206.)

For the seven weeks of this first reconnaissance of the Bay, Smith and his men sailed back and forth across the Bay.  The one clear reference to the Calvert Cliffs (though they named them something else) came after the explorers encountered a vicious storm which threatened to sink the boat, forcing them to lay over for two days among some islands on the eastern side of the Bay.  These islands they named Limbo, presumably because the continuing stormy weather kept them in limbo.  After repairing the fore sail with their shirts (lovely detail), they were convinced by the lack of fresh water to sail west toward the opposite shore.
. . . we passed by the straights of Limbo, for the weasterne shore.  So broad is the bay here, that we could scarse perceiue the great high Cliffes on the other side.
By them, wee anc[h]ored that night, and called them Richards Cliffes. (p. 111)
Richards Cliffes are the Calvert Cliffs.  On the map below, they are indicated by arrow number 3.  Jamestown is number 1.  Number 2 marks the mouth of the Patuxent River where the Calvert Cliffs begin (or end, depending upon how you come upon them).

That’s it.  No other direct reference to the Cliffs that I can find in these narratives.  A bit disappointing, I must admit.

Much of Chapter V is devoted to stories of encounters with the native peoples which often began with hostility.  But, at least, this particular exploration of the Bay was apparently without much shed blood.  Indeed, the best of the chapter are some anecdotes told with wry humor.  For example, the authors noted, with certain hyperbole, that in some places on the Bay the fish were so abundant and crowded together that they held their heads up out of the water.  In lieu of nets,
. . . we attempted to catch them with a frying pan; but we found it a bad instrument to catch fish with.  Neither better fish, more plenty or variety, had any of us ever seene in any place, swimming in the water, then in the bay of Chesapeack : but there [sic] not to be caught with frying-pans.  (p. 113)
On the return voyage, the barge ran aground on a shoal.  While waiting for the tide to come in, the men, following Smith’s lead, speared fish in the water with their swords.  (This is a telling comment on the clarity of Bay waters four centuries ago.)  Smith speared a stingray which, as he sought to remove it from his sword point, whipped its tail and stuck its barb into his wrist.  Within four hours, Smith’s hand, wrist, and shoulder had swollen, accompanied by great pain.  Fearing the Captain’s end was at hand, the men prepared his funeral and a gravesite on a nearby island.  But doctor Russell applied “a precious oile” which, apparently, saved Smith’s life.  The narrative noted that he had recovered sufficiently by nightfall that he regained his appetite and dined on his attacker.  They named the island Stingeray Ile.  (Number 4 on the map.)

Appropriately, one of the finds on my most recent expedition to the Bay was this piece of a small ray barb fossil.

This first voyage of discovery into the Bay ended with the expedition playing a trick on those manning the fort protecting Jamestown.  (I don't understand what might have inspired them to do this.)  They sailed up the river having festooned the barge with “painted streamers and such devises” as would make the watchers believe it was a Spanish frigate approaching.  The authors don’t describe the colonists’ reaction to this deception, but it’s not hard to imagine.

Immediately upon their arrival, Smith was part of a change in government of the colony.  Asked to take on the presidency, Smith tapped his friend Matthew Scrivener instead.  Then, though Scrivener lay ill, the spirited Smith launched his second expedition to the Bay a mere three days after his return.  I guess things were better in an open boat on the Chesapeake, dealing with storms, clashes with native tribes, and stingrays, than staying in the fractious colony.  He may still be sailing along the Calvert Cliffs.

Wednesday, February 1, 2012

Ordovician Limestone ~ Waiting for Castiglione

Giovanni Benedetto Castiglione (1609 – 1664) was one of the Baroque’s preeminent artists.  His drawings, etchings, and paintings reflect the masters he studied and learned from, artists such as Rubens and Rembrandt.  Yet his works are exquisitely his own, as the new exhibit (The Baroque Genius of Giovanni Benedetto Castiglione) at the National Gallery of Art in Washington, D.C. makes abundantly clear.  Indeed, the exhibit’s materials describe his etchings as “the most distinctive of any Italian artist of the period.”  In turn, Castiglione influenced a subsequent generation of artists including members of the Tiepolo family of Venice, among others.

I didn’t know I’d been waiting for this exhibit, but I had, ever since I acquired a small slab of Ordovician limestone.  A singular aspect of much of Castiglione’s work offers the connection to my piece of fossil-bejeweled rock.  At least it does in my eyes.

The National Gallery of Art’s exhibit takes a fascinating approach to its display of this selection of Castiglione’s drawings and etchings, hanging them next to works by the artists who influenced him, those who taught him, those he explored.  But even more than that, this exhibit presents us with works by the artists who felt his influence.  There, side by side by side, one can discern that which sets much of what Castiglione drew and etched apart from the works of those who preceded him and those who followed him.  As I walked the gallery rooms of the exhibit, I often could tell from a distance which were Castiglione’s pieces.  They have an energetic density.

A couple of examples may suffice to show this aspect of his work.  (These images are from Wikimedia Commons and are in the public domain.)  Castiglione’s etching of Circe Changing Ulysses’ Men into Beasts, a work from late in life, allows a white space to encircle Circe, but it’s a dynamic space, being intruded upon by branches and a hanging cloth, and the shadows appear ready to overtake it.  The remainder of the paper is densely populated.  Details abound.

In Noah Leading the Animals into the Ark, executed in brush and oil paint, there is action everywhere, even in the sky.  Castiglione blurred and blended foreground, middle ground, and background, giving us no empty space between each.

Of this latter work, Anne Midgette, who reviewed the exhibit for the Washington Post, (January 30, 2012), observes
[It is a] lyrical image of Noah leading the animals onto the Ark, every corner of the paper crackling with activity as the animals curl in a kind of wave toward the gangplank, guided by Noah’s pointing arm.
Indeed, she identifies this as one of the main aspects of this collection of Castiglione’s work.
But he was never careless in his use of paper. There is very little white space, or down time, in Castiglione’s works here; they are all-over compositions, filling every square inch of the surface, art actively happening everywhere you look.
As for my slab of Ordovician limestone?

This little chunk of rock, six inches long on the diagonal from lower left corner to upper right, has sat on my desk for a couple of weeks and for that time I’ve wondered how best to describe it.

Now and then I’ve taken a jeweler’s loupe and lost myself in a visual tour of its many mysteries.  The sheer abundance of the fossils on this rock is staggering.  This fossil-filled rock captures some of the sheer exuberance of the Ordovician ocean that covered Indiana some 470 to 444 million year ago.  According to paleontologist Lynne Clos, “The greatest diversification in the history of animal life took place during the Ordovician.”  (North America Through Time:  A Paleontological History of Our Continent, 2008, p. 37.)

Provenance of this rock?  It’s an acquisition, not a find, coming with a label identifying it as from the Brookville Formation in Indiana.  As I soon learned, this follows the local designations advocated by the late Helen Hay, who was a geologist at Earlham College.  (Helen Hay and Jon Branstrator, Guide to Field Trips, National Association of Geology Teachers, East – Central Section, September 23-24, 1989.)  The formal name recognized by the Indiana Geological Survey and the U.S. Geological Survey is the Dillsboro Formation which applies to several of the formations identified by Hay, all of them Upper Ordovician.

The most obvious of the fossils embedded in the limestone are the shells of brachiopods, bivalved marine invertebrates which flourished during the Ordovician.  Each of their valves or shells has equilateral symmetry (divisible into two equal pieces), but each creature’s two shells (top and bottom valves) are dissimilar.  Most of those on the rock appear to be of the genus Strophomena.  The picture below shows a close-up view of the interior of a ventral shell from what is perhaps S. planumbona.  Overlapping it on the upper left is, I believe, the exterior of a dorsal shell from the same species.  Characteristically, the exterior dorsal shell of this species is prominently convex toward the outer (curved) edge.

But as one’s perspective dissolves from the long shot to the medium shot and then to the close-up more, much more, comes into view.  We are drawn into a new world of myriad fossils and fragments of fossils.  It’s a phenomenon of fossiliferous limestone.  Nearly everywhere one turns there’s something different to explore.  From the previous picture, we pan up right and several pocked stalks of bryozoans come into view.  These are the calcareous structures the minute colonial invertebrates built and left behind.  Genus and species?  Beyond my ken.

We zoom in even closer and the fossilized remains of sea lilies or crinoids appear.  All we have on this rock are small, perforated disks.  These are the complex invertebrate’s columnals, the skeletal ossicles that covered the stem anchoring the animal in place.  With this close-up view, the wonderful variety of the ossicles emerges, from squared outlines to "five-dimpled" interiors (you'll see what I mean by the latter).  Once again, as we come ever closer, any ability to identify what emerges abandons me.  A extensive, detailed guide just to the shape and patterns of the columnal ossicles would be grand, but, alas, . . . I have to assume identification of genus and species cannot be based on those alone.  [Later note:  But see comment and response below.]

Although I have drawn on the movies for this tour (long shot, pan, . . .), I now think my journey through the Castiglione exhibit offers me the perfect simile for this fossil-filled limestone.
It is like a Castiglione etching, filled with energetic density.

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