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"No subject has lately excited more curiosity and general interest among geologists and the public than the question of the Antiquity of the Human Race...[]"
Lyell 1863
The debate over the age of the earth generated an even more intriguing question: how old is humankind? Written records date back some thousands of years, but geological evidence and the fossil record show us that earth must be millions of years old. Some authors tried to reconcile this discrepancy by assuming a succession of worlds, each destroyed by a global catastrophe. Therefore the "age or reptiles" could be very ancient, the ice age mammals more recent and the final catastrophe, creating the human world, happened probably only some thousands of years ago. This succession of worlds seemed to be in accordance both with the geological record as with the biblical chronology.
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The discovery of stone tools made by humans in layers also containing fossils of extinct animals - and therefore inhabitants of a world older than the supposed biblical deluge - was met with incredulity.
In 1837 the French physician Casimir Picard (1806-1841) excavated various fossil sites near his hometown of Abbeville, where he recovered stone tools and bones of antediluvian beasts. He published his discoveries in 1838-1840, just shortly before his death. Another amateur - Jacques Boucher de Perthes (1788-1868) - continued Picard´s work and discovered the jaw of a fossil elephant near a man-made flint-axe.
Most authors dismissed these discoveries arguing that this association was the result of taphonomic processes, as bones and tools became mixed together by agents like water, animals or even modern humans. Some authors even considered all the discovered human fossils as fakes.
The most compelling evidence to support the antiquity of man was collected in 1858 during excavations in Windmill Hill Cave near the city of Brixham (Devonshire, England) by William Pengelly (1812-1894), a self-educated archaeologist. The cave was found untouched, the entrance sealed off by debris and stalagmites, proof that no living thing had entered the cave for thousands of years. Most important, the excavations were done by geologists, following the principles of the young science of stratigraphy.
Every uncovered layer of the floor of the cave was carefully mapped and the location of the fossils (bones of elephant, lion, bear and reindeer) and stone tools registered.
In the same period similar discoveries were made in France. In 1867, during the universal exposition in Paris , Édouard Lartet (1801-1871), a French lawyer, presented stone tools found in sediments and caves of the valley of the Vèzère. The most intriguing artifacts were bones with engravings of ice age animals - evidence that prehistoric men met these animals.
Fig.1. Ancient rock carving, collection of the museum in Les Eyzies-de-Tayac-Sireuil, valley of the Vèzère.
Finally in 1861, influenced by Charles Darwin's explanation of the natural origin of all species on earth (including humans), eminent geologist Charles Lyell will publish "The Geological Evidence of the Antiquity of Man...[]" and establish the ancient origin of humankind as scientific fact.
Bibliography:
COHEN, C. (1998): Charles Lyell and the evidences of the antiquity of man. In: BLUNDELL, D.J. & SCOTT, A.C. (eds) Lyell: the Past is the Key to the Present. Geological Society, London, Special Publications, 143: 83-93
LYELL (1863): The Geological Evidence of the Antiquity of Man, with Remarks on Theories of the Origin of Species by variation.
PRESTWICH, J. (1860): On the occurrence of flint implements, associated with the remains of extinct mammalia, in undisturbed beds of the late geological period. Proceedings of the Royal Society of London, 10: 50-59
RUDWICK, M.J.S. (2008): Worlds before Adam - The Reconstruction of Geohistory in the Age of Reform. The University of Chicago Press: 614