CHAPTER V. 



FOSSILS— THEIR NATURE AND INTERPRETATION, AND 

 THE GEOLOGICAL RANGE OF ORGANISMS. 



Fossils of Vegetable and Animal Origin. — Having explained 

 the nature of the series of geological formations, their classi- 

 fication into systems, the value of these as reservoirs of in- 

 formation regarding the history of organisms, we next inquire 

 into the nature of the fossils, which are preserved in them and 

 furnish the records of the separate lives whose history we 

 would trace. 



Fossils are any traces, of any organisms which, having 

 been buried in rock-forming muds, are preserved to tell of 

 the life of the dead organisms. Vegetable fossils are remains 

 of plants, leaves, stems, wood, fruit, nuts, or resin, gum, or 

 carbonaceous matter, coal or bitumen, or oil or gas. Animal 

 fossils are remains of animals, their foot-prints, tracks, trails, 

 cases formed of particles of sand, as of the Caddis-worm, etc., 

 skeletal or dermal hard parts, bones, teeth, spines, scales, 

 shells, or corals, and secretions of various kinds, formed during 

 life for protection or defense, or offensive weapons, or ex- 

 cretions, when of suf^ficient hardness to resist destruction, as 

 the coprolites of fish and reptiles, preserving, in some cases, 

 evidence of the shape of the intestinal canal (spiral) through 

 which they passed. 



Original Material of Fossils. — The original materials were as 

 various as the hard parts now formed by living organisms. 

 The great majority of the known fossils were originally com.- 

 posed of calcic carbonate, calcic phosphate, chiton, bone, silica, 

 or, in the case of plants, bituminous matter. In some cases 

 the whole animal may be preserved, as in the case of insects 

 in amber, or the fossil elephants in the ice of northern Si- 

 beria, which have furnished abundant store of ivory to enter- 



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