74 [Assembly 



The fossils erf the Coal measures are almost entirely vegetable. 

 In the slates above the coal seams, most perfect and beautiful 

 impressions of leaves occur in profusion ; and large trunks or 

 stems are found, almost always compressed to a thickness of only 

 an inch or two, though two feet or more in width. The greater 

 part of these trees seem to have been allied to the tree-ferns of 

 tropical climates, though there are remains of cone-bearing trees 

 and several other vegetable families. The character of. this 

 fossil' vegetation would seem to indicate that at the time it grew, 

 a far milder climate than that now known prevailed over the 

 temperate and arctic zones ; and the tropical forms of many fos- 

 sils of the older rocks (such as the nautilus-like shells), confirm 

 us in this opinion. 



A small collection of the vegetable fossils of the Coal forma- 

 tions is displayed in a case at the end of the New- York Collec- 

 tions, next to that containing the CatskilL and Conglomerate 

 fossils. They are few, but serve to give the inexperienced 

 observer a general idea of the character of these relics. 



The belief that the coal is of vegetable origin, seems to explain 

 why the lower rocks which form the State of New- York contain 

 no coal. They appear to have been formed before terrestrial 

 vegetation flourished to an extent sufficient to form accumula- 

 tions of this substance. The first relics of land plants are found 

 in the Hamilton group ; above which they become more nume- 

 rous, and in the Catskill group are quite abundant, forming 

 occasionally miniature coal seams an inch thick. In the great 

 Carboniferous formation, they increase suddenly to an enormous 

 quantity, and in later formations are found in considerable, but 

 generally in less abundance ; and though coal is found in smaller 

 quantities in newer rocks, such as the Jurassic and Tertiary, it 

 seems never to have been formed in such profusion as in what is 

 called the Carboniferous period.* 



* The Coal or Lignite beds of the central part of the continent near the Rocky mountains> 

 appear to be of a much later date, and to belong to the Tertiary rocks. The same is true of 

 the coal of Vancouver's island on the Pacific. The coal beds near Richmond, Virginia, are 

 of an intermediate age. The conclusions to be drawn from our present knowledge are, that 

 good coal may be sometimes found above the Great Carboniferous system, hixt never below it. 



