footprints, shells and bones as the remnants of gods, heroes, saints and monsters. The cyclops, griffins and numerous other beings of myth and legend were not just figments of human imagination but monsters restored from the remains of creatures dead for millions of years. It was no different among the Native Americans of North America. The Tuscaroras, Iroquois, Onondagas and many other tribes had legends inspired by fossils, including the Lenape of the Delaware Valley.

At the time Europeans arrived in North America the Lenape occupied the land from northern Delaware to the Hudson Valley of New York, and in the blood-red sandstone of this range they saw three-toed, clawed footprints. According to one tale, passed down by Richard Calmet Adams, some of these were said to be the footprints of the primeval progenitor of all the great monsters of the land and sea. It was a living horror, the destroyer of all it could dig its claws into, but perished when it was trapped in a mountain pass and obliterated by lightning.

Europeans that settled in the Connecticut Valley noticed the tracks, too. While plowing his father’s field in South Hadley, Massachusetts, around 1802 a young man named Pliny Moody turned up slabs of rock indented with weird footprints. At least one of these curiosities was appropriately put to use as a doorstep, and visitors to the Moody farm sarcastically remarked that the Pliny’s family must have raised some hearty chickens if they left footprints in solid stone. The physician Elihu Dwight, who later bought the slab, had a different interpretation. To him the tracks were made by Noah’s raven when the biblical Deluge subsided.

Such tracks were hardly unique. The abundant three-toed footprints were often called “turkey tracks” (although many indicated turkeys bigger than a full-grown human), and a cache of the impressions were discovered by laborers quarrying flagging stones near Greenfield,Massachusetts, in 1835. These were brought to the attention of the local physician James Deane, who knew they were not made by antediluvian poultry or biblical birds. Just what had created them, though, Deane could not say, and so he contacted Amherst geology professor Edward Hitchcock and Yale academic Benjamin Silliman for their opinions.

Hitchcock was initially skeptical of Deane’s claims. Some mundane geological phenomenon could have produced tracklike marks, the professor cautioned, but Deane was adamant that the footprints were genuine. Deane sent Hitchcock a cast of one of the footprints to support his case, and despite his doubts Hitchcock was intrigued. Hitchcock soon set out to have a look at the Greenfield tracks for himself and found that Deane was right. The impressions were the footsteps of ancient creatures that had trod the Connecticut Valley long before humans had settled there.

Hitchcock became enthralled by the tracks. He collected and purchased as many as he could. He fancied himself a scientific pioneer. Although Deane was also researching the tracks, Hitchcock was the first to publish on them in an 1836 issue of the American Journal of Science. There was a variety of footprint types, each given a unique binomial name to indicate a different species, but the three-toed ones were some of the most remarkable. They ranged from giant tracks over seventeen inches long to tiny impressions less than an inch from front to back. A few large slabs even showed the strides of the animals, and the only reasonable conclusion was that they had been made by birds that flocked along the ancient shoreline. “Four out of five, I presume, would draw this conclusion at once,” Hitchcock noted, and he thought that the tridactyl footprints were made by extinct equivalents of storks and herons that strode along the banks of an ancient lake or river.

Hitchcock was deeply inspired by the varied assemblage of birds that had once lived in the Connecticut Valley, and he attempted to do justice to his fascination in the anonymously published poem “The Sandstone Bird.” In the geologist’s verse, science is placed in the guise of a sorceress who conjures up the most majestic of the primeval birds:

Bird of sandstone era, wake!
From thy deep dark prison break.
Spread thy wings upon our air, Show thy huge strong talons here:
Let them print the muddy shore
As they did in days of yore.
Pre-adamic bird, whose sway
Ruled creation in thy day,
Come obedient to my word,
Stand before Creation’s Lord.

So restored, Hitchcock’s fictional bird could only lament the dismal state of the modern world. The earth was cold and the impressive giants it knew so well were all gone. Even the trees were so Lilliputian that the dinosaur “Iguanodon could scarce here find a meal!” The haughty bird could not stand the sight of what had become of its home.

. . . all proclaims the world well nigh worn out,
Her vital warmth departing and her tribes,
Organic, all degenerate, puny soon,
In nature’s icy grave to sink forever.
Sure ’tis a place for punishment designed,
And not the beauteous happy spot I loved.
These creatures here seem discontented, sad:
They hate each other and they hate the world,
I can not, will not, live in such a spot.
I freeze, I starve, I die: with joy I sink,
To my sweet slumbers with the noble dead.

The sullen bird was then swallowed up by the earth, leaving the geologist with no evidence to prove what he had seen. Hitchcock was in a similar bind. No skeleton had been found to reveal the true form of his birds. Storks and herons provided fair analogs, but even the largest of the living wading birds was puny compared to the birds that made the largest fossil tracks. Without skeletons, Hitchcock could only guess what they looked like.

At the same time that Hitchcock was researching the Connecticut Valley tracks, Richard Owen was examining a strange chunk of bone from New Zealand. It was said to have belonged to an enormous eagle, but Owen took it to be part of the femur of a gargantuan, ostrichlike bird he called Dinornis (commonly known as the moa). From the osteological scrap he reconstructed an entire skeleton, and it was later proven to be correct when more remains of the flightless birds were found. Owen had raised a giant bird from the dead, and it provided the perfect proxy for the sandstone birds.

For Hitchcock, though, there were more than just scientific lessons to be learned from the tracks. What he saw in the fossil record spoke of God’s benevolence, and he expounded upon this belief as a Congregationalist pastor and professor of natural theology at Amherst. (Part of his inspiration for collecting so many tracks was to build a testament to God’s glorious works in nature.) He was astonished by the vast array of stupendous creatures that crawled, swam, flew, and dashed over the surface of the earth in time immemorial. Though facts from the geological strata were shaking the foundations of a literal interpretation of Genesis, Hitchcock attempted to bridge the gap between geology and theology as the Bridgewater Treatises had in England. In his Ichnology of New England Hitchcock concluded:

And how marvellous the changes which this Valley has undergone in its inhabitants! Nor was it a change without reason. We are apt to speak of these ancient races as monstrous, so unlike existing organisms as to belong to another and quite different system of life. But they were only wise and benevolent adaptations to the changing condition of our globe. One common type runs through all the present and the past systems of life, modified only to meet exigencies, and identifying the same infinitely wise and benevolent Being as the Author of all. And what an interesting evidence of his providential care of the creatures he has made, do these modifications of structure and function present! Did the same unvarying forms of organization meet us in every variety of climate and condition, we might well doubt whether the Author of Nature was also a Providential Father. But his parental care shines forth illustriously in these anomalous forms of sandstone days, and awakens the delightful confidence that in like manner he will consult and provide for the wants of individuals.

If God provided for birds that could neither sow nor reap their own food surely He would have also cared for the enormous avians of old (and even more so the human “lords of creation”). Hitchcock believed that only God could have so perfectly fitted organisms to their surroundings, but this view of nature crumbled as naturalists increasingly tried to understand nature on its own terms and not as a moral lesson. Charles Darwin’s 1859 treatise slammed the door shut on the concept of natural theology as science, which Hitchcock subscribed to, but this new perspective on life’s history raised new questions.

Birds were so different from other vertebrates that they appeared to be perched on their own lonely branch in the tree of life. How could they have evolved? Hitchcock’s tracks hinted that true birds had been present nearly as long as reptiles and amphibians, and the discovery of a fossil feather in 1860 from Solnhofen, Germany, did nothing to change this quandry. Found in the Jurassic-aged limestone of a quarry mined for stone to make lithographic plates, the delicate fossil was acquired by the German paleontologist Christian Erich Hermann von Meyer. In 1861 he named it Archaeopteryx lithographica, the “ancient feather from the lithographic limestone.”

Not long after von Meyer described the feather, another nearby limestone quarry produced an enigmatic skeleton. The jumbled creature had a long bony tail but was surrounded by feather impressions; it was as much a reptile as it was a bird. Rather than going straight to a museum, however, the specimen was given to the local physician Karl Häberlein in exchange for medical services.

Rumors of the specimen began to circulate among naturalists, but Häberlein would not part with it easily. He stipulated that the fossil would only be sold along with the rest of his fossil collection, raising the cost beyond the reach of many prospective buyers. Richard Owen and George Robert Waterhouse, certain that Archaeopteryx would bring prestige to the British Museum, were able to convince the trustees of the institution to forward £700 for the fossil (or what the museum would normally have spent on new fossil acquisitions over the course of two years). By November 1862 the fossil was in London.

Some German naturalists were upset that the slab had been expatriated to England, but the august University of Munich professor Johann Andreas Wagner had opposed efforts to acquire Archaeopteryx for his college. He was sure it was not all it seemed. Although Häberlein tried to restrict access to the specimen amid rumors it was a fake, a verbal report and sketch of the fossil reached Wagner, who argued that rather than a bird, it was a kind of reptile he called Griphosaurus, or “riddle reptile.”

Wagner’s fears over evolution had spurred his impulsive description. Archaeopteryx sounded like just the type of transitional form that would throw support to Darwin and Wallace’s evolutionary theories, and Wagner’s warnings about the fossils were among the last of his publications before his death.

Owen’s description of the fossil was read before the Royal Society in 1863. He appraised it as the “by-fossil-remains-oldest-known feathered Vertebrate.” More than that, the fossil was most certainly a bird despite its reptilian characteristics, and Owen upheld von Meyer’s original name Archaeopteryx. This diagnosis allowed Owen to make a particular prediction. The head of Archaeopteryx was missing, but Owen reasoned that “by the law of correlation we infer that the mouth was devoid of lips, and was a beak-like instrument fitted for preening the plumage of Archaeopteryx.”

While some naturalists felt that Owen’s description was rather crude, the news of the fossil was welcome among evolutionists. In an 1863 letter to Darwin the fossil mammal expert Hugh Falconer beamed,

Had the Solenhofen quarries been commissioned — by august command — to turn out a strange being à la Darwin — it could not have executed the behest more handsomely — than in the Archaeopteryx.

This news made Darwin eager to hear more about the “wondrous bird,” yet he ultimately did little to present Archaeopteryx as a confirmation of his evolutionary ideas. In the fourth edition of On the Origin of Species published in 1866, Darwin primarily used Archaeopteryx and Hitchcock’s tracks — by now thought to have been made by dinosaurs — to illustrate that the fossil record still had secrets to divulge. “Hardly any recent discovery,” Darwin wrote of Archaeopteryx, “shows more forcibly than this how little we as yet know of the former inhabitants of the world.” Even as it hinted at a connection, Archaeopteryx was too weak to unequivocally bridge the gap between reptiles and birds by itself. The necessary evidence would be supplied by the anatomist Thomas Henry Huxley.

Huxley began his scientific career in 1846 by studying marine invertebrates while serving as an assistant surgeon aboard the HMS Rattlesnake. His work was well received by other naturalists, and when he returned to England in 1850 he was set to establish himself among the scientific elite. Like the man who would become his rival, Richard Owen, Huxley was most concerned with the underpinnings of anatomical form, but where Owen cloaked his work in pious rhetoric, Huxley’s distaste for religious interference in science may have attracted him to Darwin’s theory of evolution in the first place. While Huxley disagreed with Darwin on some key points, natural selection was the best mechanism yet proposed for evolutionary change. For natural selection to make sense, however, the absence of graded transitions in the fossil record had to be accounted for, which Huxley explained through the concept of “persistent types.”

Throughout the fossil record there seemed to be little evolutionary change; crocodiles looked like crocodiles no matter what strata they came from. Instead of being evidence against evolution, however, Huxley proposed that the persistent forms were echoes of evolutionary changes that had occurred in a time so distant that it was not recorded in the rock. If most of evolution happened during “non-geologic time,” then the inability of naturalists to explain the origin of major groups of animals with fossil evidence became a moot point. The caprices of geology kept them out of science’s reach.

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Authors: Brian Switek

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