on； a basis on which you can tell that thosecarboniferous rocks from devon are younger than these cambrian rocks from wales。 smith鈥檚insight was to realize that the answer lay with fossils。 at every change in rock strata certainspecies of fossils disappeared while others carried on into subsequent levels。 by noting which species appeared in which strata； you could work out the relative ages of rocks wherever theyappeared。 drawing on his knowledge as a surveyor； smith began at once to make a map ofbritain鈥檚 rock strata； which would be published after many trials in 1815 and would bee acornerstone of modern geology。 （the story is prehensively covered in simonwinchester鈥檚 popular book the map that changed the world 。）unfortunately； having had his insight； smith was curiously uninterested in understandingwhy rocks were laid down in the way they were。 鈥渋 have left off puzzling about the origin ofstrata and content myself with knowing that it is so；鈥潯e recorded。 鈥渢he whys and whereforescannot e within the province of a mineral surveyor。鈥�
smith鈥檚 revelation regarding strata heightened the moral awkwardness concerningextinctions。 to begin with； it confirmed that god had wiped out creatures not occasionally butrepeatedly。 this made him seem not so much careless as peculiarly hostile。 it also made itinconveniently necessary to explain how some species were wiped out while others continuedunimpeded into succeeding eons。 clearly there was more to extinctions than could beaccounted for by a single noachian deluge； as the biblical flood was known。 cuvier resolvedthe matter to his own satisfaction by suggesting that genesis applied only to the most recentinundation。 god； it appeared； hadn鈥檛 wished to distract or alarm moses with news of earlier；irrelevant extinctions。
so by the early years of the nineteenth century； fossils had taken on a certain inescapableimportance； which makes wistar鈥檚 failure to see the significance of his dinosaur bone all themore unfortunate。 suddenly； in any case； bones were turning up all over。 several otheropportunities arose for americans to claim the discovery of dinosaurs but all were wasted。 in1806 the lewis and clark expedition passed through the hell creek formation in montana； anarea where fossil hunters would later literally trip over dinosaur bones； and even examinedwhat was clearly a dinosaur bone embedded in rock； but failed to make anything of it。 otherbones and fossilized footprints were found in the connecticut river valley of new englandafter a farm boy named plinus moody spied ancient tracks on a rock ledge at south hadley；massachusetts。 some of these at least survive鈥攏otably the bones of an anchisaurus； whichare in the collection of the peabody museum at yale。 found in 1818； they were the firstdinosaur bones to be examined and saved； but unfortunately weren鈥檛 recognized for what theywere until 1855。 in that same year； 1818； caspar wistar died； but he did gain a certainunexpected immortality when a botanist named thomas nuttall named a delightful climbingshrub after him。 some botanical purists still insist on spelling it wistaria 。
by this time； however； paleontological momentum had moved to england。 in 1812； atlyme regis on the dorset coast； an extraordinary child named mary anning鈥攁ged eleven；twelve； or thirteen； depending on whose account you read鈥攆ound a strange fossilized seamonster； seventeen feet long and now known as the ichthyosaurus； embedded in the steep anddangerous cliffs along the english channel。
it was the start of a remarkable career。 anning would spend the next thirty…five yearsgathering fossils； which she sold to visitors。 （she is monly held to be the source for thefamous tongue twister 鈥渟he sells seashells on the seashore。鈥潱he would also find the firstplesiosaurus； another marine monster； and one of the first and best pterodactyls。 though noneof these was technically a dinosaur； that wasn鈥檛 terribly relevant at the time since nobody then knew what a dinosaur was。 it was enough to realize that the world had once held creaturesstrikingly unlike anything we might now find。
it wasn鈥檛 simply that anning was good at spotting fossils鈥攖hough she was unrivalled atthat鈥攂ut that she could extract them with the greatest delicacy and without damage。 if youever have the chance to visit the hall of ancient marine reptiles at the natural history museumin london； i urge you to take it for there is no other way to appreciate the scale and beauty ofwhat this young woman achieved working virtually unaided with the most basic tools innearly impossible conditions。 the plesiosaur alone took her ten years of patient excavation。
although untrained； anning was also able to provide petent drawings and descriptions forscholars。 but even with the advantage of her skills； significant finds were rare and she passedmost of her life in poverty。
it would be hard to think of a more overlooked person in the history of paleontology thanmary anning； but in fact there was one who came painfully close。 his name was gideonalgernon mantell and he was a country doctor in sussex。
mantell was a lanky assemblage of shortings鈥攈e was vain； self…absorbed； priggish；neglectful of his family鈥攂ut never was there a more devoted amateur paleontologist。 he wasalso lucky to have a devoted and observant wife。 in 1822； while he was making a house callon a patient in rural sussex； mrs。 mantell went for a stroll down a nearby lane and in a pile ofrubble that had been left to fill potholes she found a curious object鈥攁 curved brown stone；about the size of a small walnut。 knowing her husband鈥檚 interest in fossils； and thinking itmight be one； she took it to him。 mantell could see at once it was a fossilized tooth； and aftera little study became certain that it was from an animal that was herbivorous； reptilian；extremely large鈥攖ens of feet long鈥攁nd from the cretaceous period。 he was right on allcounts； but these were bold conclusions since nothing like it had been seen before or evenimagined。
aware that his finding would entirely upend what was understood about the past； and urgedby his friend the reverend william buckland鈥攈e of the gowns and experimental appetite鈥攖o proceed with caution； mantell devoted three painstaking years to seeking evidence tosupport his conclusions。 he sent the tooth to cuvier in paris for an opinion； but the greatfrenchman dismissed it as being from a hippopotamus。 （cuvier later apologized handsomelyfor this uncharacteristic error。） one day while doing research at the hunterian museum inlondon； mantell fell into conversation with a fellow researcher who told him the tooth lookedvery like those of animals he had been studying； south american iguanas。 a hastyparison confirmed the resemblance。 and so mantell鈥檚 creature became iguanodon ； aftera basking tropical lizard to which it was not in any manner related。
mantell prepared a paper for delivery to the royal society。 unfortunately it emerged thatanother dinosaur had been found at a quarry in oxfordshire and had just been formallydescribed鈥攂y the reverend buckland； the very man who had urged him not to work in haste。
it was the megalosaurus； and the name was actually suggested to buckland by his friend dr。
james parkinson； the would…be radical and eponym for parkinson鈥檚 disease。 buckland； it maybe recalled； was foremost a geologist； and he showed it with his work on megalosaurus。 in hisreport； for the transactions of the geological society of london ； he noted that the creature鈥檚teeth were not attached directly to the jawbone as in lizards but placed in sockets in themanner of crocodiles。 but having noticed this much； buckland failed to realize what it meant：
megalosaurus was an entirely new type of creature。 so although his report demonstrated littleacuity or insight； it was still the first published description of a dinosaur； and so to him rather than the far more deserving mantell goes the credit for the discovery of this ancient line ofbeings。
unaware that disappointment was going to be a continuing feature of his life； mantellcontinued hunting for fossils鈥攈e found another giant； the hylaeosaurus； in 1833鈥攁ndpurchasing others from quarrymen and farmers until h