Passage IV

NATURAL SCIENCE: This passage is adapted from the essay "Archives of Life: Science and Collections" by Richard Fortey (@2010 by Richard Fortey).

Safely stored behind the scenes at the Natural History Museum in London is a slightly twisted vertebrate skeleton preserved on a slab of creamy white limestone. This particular specimen was discovered in quarries near Solnhofen in southern Germany in 1861. The fine limestones of Solnhofen are ideally suited to making lithographic stones, and in the nineteenth century lithographs provided one of the most important means of book illustration—indeed lithographic stones of this quality are still in demand by artists today. Vast quantities of this lithographic limestone of Jurassic age—about 150 million years old—have been taken out of opencast workings, where the rocks can be split into convenient slabs a centimetre or two thick. On many of these flat-surfaced pieces of rock, fossils are laid out like gifts on a salver.

Some Solnhofen fossils are rather common, such as those of delicate little sea lilies. Others are both rare and more spectacular. There are a great variety of fish species known nowhere else, for example. The fossil horseshoe crab Mesolimulus provides evidence that its living relatives breeding each year along the Atlantic coast of America have changed little over tens of millions of years. Delicate flying reptiles—half a dozen species or so of pterodactyl—testify by contrast to creatures that have vanished from the Earth forever. A few species of dinosaur are known, of the most delicate sort (Compsognathus), and quite unlike the monsters of popular imagination. Insects include dragonflies (Aeschnogomphus) whose every wing-vein is visible as delicate tracery. All these creatures are preserved in rocks which originated as tacky muds flooring a lagoon that lay offshore from a richly biodiverse habitat. Such special circumstances sampled and preserved a much wider variety of organisms than the usual fossil locality, and the wide range of fossils provides a rare window into an entire habitat from a very different world. Yet if the remains were not kept carefully in museums all this evidence of past life would perish, and new generations of children and scholars could not interrogate the past. Local museums at Eichstätt and Solnhofen fulfil that function for those who would come to Bavaria and marvel at its geological treasures. But some of the specimens from the Solnhofen limestone have a relevance that extends far beyond the reconstruction of the late Jurassic scene, and these specimens are treasures in the collections of museums around the world. None more so than that specimen—a mere 35 cm at its longest—safely curated in the Natural History Museum in London.

For this is the first example ever discovered of the early bird Archaeopteryx. It remains one of the most important specimens in the British national collections. The next complete fossil bird of the same species—the so-called Berlin specimen—was found sixteen years later. It would be difficult to overstate the importance of this London specimen of Archaeopteryx in the history of biology.

First, the date of its discovery is only two years after the publication of The Origin of Species. Charles Darwin famously described what he called 'difficulties on theory' in that work, where he anticipated a number of criticisms that he expected his great idea to encounter. Prime among these was 'the rarity or absence of intermediate forms' in the fossil record. Second, the detailed scientific description of Archaeopteryx was an accomplishment of Richard Owen in 1863; he was later to become first director of the Natural History Museum. Owen was no Darwinian, but he was an able anatomist. It must have proved anathema to him when Archaeopteryx was recruited as probably the best example of an 'intermediate form' and one that had turned up with the impeccable timing usually associated with a good piece of theatre. Its amalgam of reptilian and bird features (feathers and wishbone among them) was a striking vindication of the notion of descent with modification, and a rebuttal to those who might wonder how it was possible for animals to make the transition from earth to the skies.

In this sense Archaeopteryx became a kind of talisman for evolution. Owen was enough of a 'Museum man' to ensure that this fossil was safely curated, and part of any museum’s function is just that—to protect material regardless of the current explanations of its importance. The old bird has now been joined by half a dozen or so subsequent examples worldwide, but its importance has not diminished over the years.