FOSSILS OF THE TRIAS, OOLITE, ETC. 69 



derived from the circumstance that this formation 

 exhibits a triple series of limestone, sandstone and 

 variegated marls, and conglomerates, containing 

 peculiar fossils. This formation is the great 

 depository of rock salt. 



As to the organic remains the trias presents a re- 

 markable contrast with the formation immediately 

 above in the paucity of such remains. Twenty or 

 thirty kinds of ferns and cone-bearing plants have, 

 however, been attained. The animal remains are 

 numerous and various. They consist of zoophytes 

 and corals, lily encrinites, so called from their 

 resemblance to that flower; fishes of various kinds, 

 reptiles of the lizard and frog tribes, many of them 

 of vast dimensions, and one of them in particular 

 presenting a most unique and marvellous structure, 

 having a pair of huge tusks like the walrus, and 

 thence called Dicynodon or bidental ; huge birds 

 likewise appear to have belonged to this formation ; 

 their footprints have been discovered distinctly 

 marked, eighteen inches in length by fourteen in 

 breadth, deeply made originally in the mud in 

 which the creature walked. These immense birds 

 appear to have been four or five times larger than 

 an African ostrich, and must have weighed about 

 600 Ibs. 



II. The Oolite and Lias formation now claim 

 our notice. These formations, which may be con- 

 sidered as one, occur in some portions of the coasts 

 of Yorkshire and Devonshire, and also in various 

 parts of the Scottish coast. 



The fossils of these formations consist of fucoids, 



F 3 



