COMME1N CEMENT OF MAMMALIA. 



57 



There are no particular appearances of disturbance be- 

 tween the close of the new red sandstone and the begin- 

 ning of the oolite system, as far as has been observed in 

 England. Yet there is a great change in the materials of 

 the rocks of the two formations, showing that while the 

 bottoms of the seas of the one period had been chiefly 

 arenaceous, those of the other were chiefly clayey and limy. 

 And there is an equal difference between the two periods 

 in respect of both botany and zoology. While the new red 

 sandstone shows comparatively scanty traces of organic cre- 

 ation, those in the oolite are extremely abundant, particular- 

 ly in the department of animals, and more particularly still 

 of sea mollusca, which it has been observed, are always the 

 more conspicuous in proportion to the predominance of 

 calcareous rocks. It is also remarkable that the animals of 

 the oolitic system are entirely different in species from 

 those of the preceding age, and that these species cease be- 

 fore the next. In this system we likewise find that uni- 

 formity over great space which has been remarked of the 

 Faunas of earlier formations. " In the equivalent deposits 

 in the Himmalaya Mountains, at Fernando Po, in the 

 region north of the Cape of Good Hope, and in the Run 

 of Cutch, and other parts of Hindostan, fossils have been 

 discovered, which, as far as English naturalists who have* 

 seen them can determine are undistinguishable from cer- 

 tain oolite and lias fossils of Europe."* 



The dry land of this age presented cycadeae, " a beauti- 

 ful class of plants between the palms and conifers, having 

 a tall, straight trunk, terminating in a magnificent crown 

 of foliage/'! There were three ferns, but in smaller pro- 

 portion than in former ages ; also equisetaceae, lilia, and 

 conifers. The vegetation was generally analogous to that 

 of the Cape of Good Hope and Australia, which seems to 

 argue a climate (we must remember a universal climate) 

 between the tropical and temperate. It was, however, 

 sufficiently luxuriant in some instances to produce thin 

 seams of coal, for such are found in the oolite formation of 

 both Yorkshire and Sutherland. The sea, as for ages before, 

 contained algae, of which, however, only a few species 

 have been preserved to our day. The lower classes of 

 the inhabitants of the ocean were unprecedently abundant. 

 The polypiaria were in such abundance as to form wlole 



* Murchison's Silurian System, p 583. 

 t Buckland 



