12 PALEONTOLOGY OF KENTUCKY. 



objects with which palaeontology deals are known under the name of " fossils," 

 a term designating bodies "dug out of the ground," and which was formerly 

 applied to metals and rocks, as well as to organic remains. At present the 

 word fossil is used in a more restricted sense, applying only to such geological 

 objects from which science may deduce information about the organic life of 

 the past. These objects mainly consist in remains of animals and plants, such 

 as shells, teeth and bones ; or stems, leaves and fruits ; but they also include 

 the burrows and tracks of annelids, the footprints of saurians and other ani- 

 mals, and even the droppings of fishes and reptiles, which are known under 

 the name of coprolites. Some geologists class among the fossils even objects 

 produced by man, such as arrow-heads, spear-heads and canoes found in the 

 gravel and clay beds of our fields and river shores ; but, inasmuch as they 

 properly belong to archaeology, they can not be counted among the fossils. 



The real nature of fossils was known more than five hundred years before 

 the Christian era, by Xenophanes. He observed the fossil remains in the 

 quarries of Syracuse, consisting of marine shells and fish-bones. He recognized 

 them as the remains of real animals, that had lived there at the bottom, of 

 the sea, where they were imbedded in mud, which afterwards hardened into 

 the rocks then inclosing them. He also laid down the general proposition, that 

 the geographical features of our earth are not constant, but that, where land 

 now is, sea has been, and where sea now is, land has been. Afterwards this 

 clear conception of the real nature of fossils appears to have been lost, until 

 the end of the seventeenth century, when Nicholas Steno, Professor of anat- 

 omy in Florence, though a Dane by birth, gave them again a correct explan- 

 ation, and revived the theory of Xenophanes. 



Before Steno, during the fourteenth, fifteenth, sixteenth and seventeenth 

 centuries, fossils were regarded as mere figured stones, portions of mineral 

 matter which have assumed the forms of leaves and shells and bones, just as 

 those portions of mineral matter which we call crystals, take on the form of 

 regular geometrical bodies. Others considered them the products of the germs 

 of animals and of the seeds of plants, which have, as it were, lost their way, 

 in the bowels of the earth, and achieved only an imperfect and abortive devel- 

 opment. These opinions appear to us ridiculous, and we are inclined to sneer 

 at our ancestors for entertaining such ideas about a matter which is now so 

 clear and simple. People who believed in spontaneous generation, could have 

 no difficulty in taking fossils for sports of nature, and we know that spon- 

 taneous generation was generally believed in up to the present century ; and, 

 even to-day, thousands of people, laying claim to a fair education, still adhere 

 to that belief These erroneous ideas about the nature of fossils were, long 

 after Steno' s correct interpretation, maintained among common people, but 

 men of science became more and more convinced of the correctness of 



