FOSSILS, AND HOW THEY ARE FORMED 3 



objects as jelly fishes. But for these we should have 

 little positive knowledge of the outward appearance of 

 the creatures of the past, and to them we are occasion- 

 ally indebted for the solution of some moot point in their 

 anatomy. 



The reader may possibly wonder why it is that fossils 

 are not more abundant; why, of the vast majority of 

 animals that have dwelt upon the earth since it became 

 fit for the habitation of living beings, not a trace re- 

 mains. This, too, when some objects the tusk of the 

 Mammoth, for example have been sufficiently well 

 preserved to form staple articles of commerce at the 

 present time, so that the carved handle of my lady's 

 parasol may have formed part of some animal that 

 flourished at the very dawn of the human race, and been 

 gazed upon by her grandfather a thousand times re- 

 moved. The answer to this query is that, unless the 

 conditions were such as to preserve at least the hard 

 parts of any creature from immediate decay, there was 

 small probability of its becoming fossilized. These 

 conditions are that the objects must be protected from 

 the air, and, practically, the only way that this happens 

 in nature is by having them covered with water, or at 

 least buried in wet ground. 



If an animal dies on dry land, where its bones lie 

 exposed to the summer's sun and rain and the winter's 

 frost and snow, it does not take these destructive 

 agencies long to reduce the bones to powder; in the 

 rare event of a climate devoid of rain, mere changes of 

 temperature, by producing expansion and contraction, 

 will sooner or later cause a bone to crack and crumble. 



Usually, too, the work of the elements is aided by 

 that of animals and plants. Every one has seen a dog 

 make way with a pretty good-sized bone, and the 

 Hyena has still greater capabilities in that line; and 



