74 MR SMITH ON THE CHANGES 



marks on the particular shells have been added to the de- 

 scriptions which accompany the catalogues. It will be ob- 

 served, that the whole of those examined by him which are 

 still to be found recent, but not in the British seas, occur 

 in northern latitudes. This strongly confirms an opinion 

 I had previously entertained, that the indications of climate 

 which could be gathered from the organic remains of these 

 deposits pointed to a lower temperature than that of the 

 present period. It was first suggested by observing the 

 identity of many of the shells most common in them, with 

 those found by Mr Lyell at Udevalla, and figured in his 

 paper of the elevation of land in Sweden, in the Philosophi- 

 cal Transactions for 1835. Mr L. has since pointed out to 

 me the Fusus Peruvianus of Lamarck, as still inhabiting 

 the Arctic Seas. I have also had an opportunity of shewing 

 these shells to Mr Gray of the British Museum; on a cur- 

 sory examination he could not detect any of them as Bri- 

 tish, but remarked that they had all the appearance of 

 Arctic shells. In the Clyde-raised deposits, shells common 

 to Britain and the northern parts of Europe occur in much 

 greater abundance than they do at present. The Pecten 

 Islandicus, which has probably entirely disappeared, and 

 the Cyprina Islandica, which, if found recent in the Clyde, 

 is extremely rare, are amongst the most common of the 

 fossil species. 



We know too little of the Flora of this period, to be 

 warranted in drawing any inferences respecting climate from 

 it ; but the plants known to belong to it are all, such as 

 would agree with a lower temperature, and the Scots fir, 

 now only indigenous in the north of Scotland and Norway, 

 occurs in the sub-marine forests of Wales and Hampshire. 



There are, however, some of the fossil shells which have 

 been supposed to lead to conclusions of an opposite nature. 



