MARINE SHELLS IN STRATIFIED CLAYS. 77 



to the older or deep-water part of the deposit, are known as living 

 shells of" the Arctic or boreal regions of the Atlantic. About half of 

 the species are fossil in the Post-pliocene of Great Britain. The 

 great majority are now living in the Gulf of St Lawrence and on the 

 neighbouring coasts ; and more especially on the north side of the 

 gulf and the coast of Labrador. In so far, then, as marine life is 

 concerned, the modern period in this country is connected with that 

 of the boulder clay by an unbroken chain of animal existence. These 

 deposits in Lower Canada aftord no indications of the terrestrial fauna ; 

 but the remains of Elephas priim'genius in beds of similar age in Upper 

 Canada,* show that during the period in question great changes 

 occurred among the animals of the land ; and we may hope to find 

 similar evidences elsewhere, especially in localities where, as on 

 the Ottawa, the debris of land- plants and land-shells occur in the 

 marine deposits. 



The climate of this period, as indicated by its marine animals, and 

 the causes of its difference from that which now obtains in the northern 

 hemisphere, have been fertile subjects of discussions and controversies, 

 which I have no Avish here to reopen. I desire, however, to state, 

 in a manner level to the comprehension of the ordinary reader, the 

 facts of the case in so far as relates to Canada, and equally to the 

 maritime provinces, and an important inference to which they appear 

 to me to lead, and which, if sustained, will very much simplify our 

 views of this question. 



Every one knows that the means and extremes of annual tempera- 

 ture differ much on the opposite sides of the Atlantic. The isothermal 

 line of 40°, for example, passes from the south side of the Gulf of St 

 Lawrence, skirts Iceland, and reaches Europe near Drontheim in 

 Norway. This fact, apparent as the result of observations on the 

 temperature of the land, is equally evidenced by the inhabitants and 

 physical phenomena of the sea. A large proportion of the shell-fish 

 inhabiting the Gulf of St Lawrence and the coast thence to Cape Cod 

 occur on both sides of the Atlantic, but not in the same latitudes. 

 The marine fauna of Cape Cod is parallel, in its prevalence of boreal 

 forms, with that of the south of Norway. In like manner, the descent 

 of icebergs from the north, the freezing of bays and estuaries, the 

 drifting and pushing of stones and boulders by ice, are Avituessed on 

 the American coast in a manner not paralleled in corresponding 

 latitudes in Europe. It follows from this, that a collection of shells 

 from any given latitude on the coasts of Europe or America would 

 bear testimony to the existing difference of climate. The geologist 

 * lieports uf Gcol. Survey; Lyell's Travels. 



