OF CREATION. 135 



CHAPTER VIII. 



THE MARINE REPTILES, AND OTHER ANIMALS CHARACTERISTIC 

 OP THE LIAS. 



THE deposit of sand and marly beds, which must 

 have been steadily continued for a long time over ex- 

 tensive tracts at the commencement of the secondary 

 period, seems to have gradually changed to a finer, 

 more calcareous, and less sandy mud thrown down 

 from suspension in water, perhaps after it had 

 been carried for some distance by marine currents. 

 This deposit of mud was local, since, so far as we 

 can tell by examining the tracts now above water, 

 it was almost confined to a part of England and a 

 narrow tract in the middle of Europe, though it has 

 been thought traceable in the middle of Asia, and is 

 possibly represented in a small part of South America. 

 The bed is sometimes more or less sandy or calcare- 

 ous ; but we know of few contemporaneous deposits ; 

 and where the muddy beds do not appear, there is 

 often nothing intermediate between the new red 

 sandstone and the newest beds of the middle epoch. 



The most distinct beds of passage between the 

 new red sandstone and this next superior stratum, 

 (which is called Has,) are certain deposits at Aust 

 Cliff', at the mouth of the Severn, where there is a 

 thin bed absolutely made up of organic remains. 

 There are also others on the continent of Europe, in 



