KEUPER SANDSTONE AT STORETON. 181 



Elgin were mainly represented by hollow spaces in the 

 sandstone which were really the moulds of the bones 

 whose substance had been dissolved away, the sand itself 

 having sufficiently consolidated to retain their forms. If, 

 however, the solution was complete before the solidifi- 

 cation of the matrix then all traces of the presence of the 

 bones would have been lost, and this is probably the reason 

 of any trace of bones or teeth being so rare to this district. 



Any similarity between the fauna of the trias of this 

 country and that of South Africa or elsewhere is a matter 

 of interest as regards the distribution of animals. "Where 

 change of conditions depends on change of temperature 

 such change will be gradual and the conditions will move 

 continuously in a direction more or less directly north 

 and south, and the fauna and flora will readily follow. 



It is, however, generally supposed that the triassic 

 formation represents arid and desert conditions, due to the 

 cutting off of moisture bearing winds by the elevation of 

 a mountain chain or otherwise. These conditions would 

 arise in totally disconnected areas where the fauna and 

 flora migrating from one locality to another would have 

 to cross tracts of country where other conditions would 

 prevail placing them at a considerable disadvantage in the 

 struggle for existence; and much modification might be 

 expected in those forms that survived and happened to 

 reach the new locality where conditions had arisen to 

 which they were originally fitted. 



Explanation of Plate VII. 



Fig. 1. Natural Cast of a footprint from the Lower 



Keuper Sandstone of Storeton, Cheshire. 

 Fig. 2. Drawing from the same showing the characters 

 seen by Prof, H. G. Seeley. 

 p.p. Prepollex. 



2. p. Second bone of the pisiform element of 

 the carpus on the outer side. 



