CHAP. IX.] JURASSIC PERIOD. 149 



the greater number of these insects were not derived from 

 the hot low-coast territories, but were borne to the sea from 

 the more distant and lofty mountain lands (7,000 to 10,000 

 feet high), by sudden floods which are then of frequent 

 occurrence." They also, in accordance with the elevated 

 regions from whence they came, bore the characters of 

 temperate and cold climates ; and Sir A. Ramsay thinks it 

 probable " that the insect remains described by Mr. Brodie 

 were washed from the mountain country we have described 

 into the surrounding seas, and there entombed amid crea- 

 tures of a tropical character." ] 



The geography of the British region, so far as concerned 

 the relative positions of land and water, was similar to that 

 of the Triassic period. The waters of the Liassic sea 

 covered the whole area of the Triassic lake, and extended 

 some little way beyond its margins. From the southerly 

 extension of the Lias through France it would seem that 

 the southern sea gained access to the British area through 

 that country, and if this were so we can understand how 

 the Jurassic fauna and flora came to have their semi- 

 tropical character. With continental land extending far 

 to the east and%est through the northern temperate zone, 

 but not reaching far into the Arctic Circle, 2 and with an 

 open sea spreading from tropical climes to its southern 

 shores, we have exactly the conditions which would carry 

 a high temperature and tropical productions far into the 

 temperate zone. 



As to the western shore of the British sea we can only 

 say that it lay considerably to the westward of the present 

 boundary of the Trias, though probably not far beyond 



1 " Mem. Geol. Survey," vol. i. p. 325. 



2 There are Jurassic deposits in East Greenland, Spitzbergen, Northern 

 and Eastern Russia, and the fossils they contain make it improbable 

 that there was any accumulation of ice round the North Pole at this 

 time. 



