64 MR. R. D. DARBISHIRE ON MARINE SHELLS 



C. rusticum, and A. lactea) in the Macclesfield list indi- 

 cates a larger extension northwards into the basin of the 

 Irish Sea^ than now obtains^ of the so-called southern or 

 Spanish fauna. This might indeed be expected. A depres- 

 sion of the Welsh land, such as hoarded the shells of south- 

 ern Spain in the recesses of the valley of the Mersey, would 

 now heap the same species in the sources of the Dovey and 

 far up the Severn valley. 



It will be recollected, moreover, that a depression of 600 

 feet would leave only a few rocky islands on the east and 

 south of what is now the mainland of Ireland, and probably 

 carry some degrees further to the eastward that warmer 

 influence which has been ascribed to the impact of the Gulf- 

 stream on the zoologically speaking rich Atlantic shores of 

 modern Ireland. 



The tidal current alone of so weighty a mass of water 

 would carry to or maintain the species of the warmer seas 

 at their farthest extension, past the site of the present St. 

 George^s Channel. 



I am not able to state what lands would be submerged 

 by a similar depression of the country to the south-west of 

 Macclesfield. 



P.S. — I am tempted by the interest of an observation 

 which I have just made, and which bears especially on one 

 point in my remarks, to add the following : — 



Mr. Green, of the Geological Survey, called my atten- 

 tion to a patch of gravel discovered by Mr. Prestwich some 

 years ago, in which that gentleman had found fragments 

 of shells at an elevation considerably greater than that of 

 the Cemetery Hill — namely, about 1 200 feet above the sea. 

 This deposit I have just visited. 



It appears in an escarpment on the north side of a brook, 

 near the Buxton new road, about half a mile eastward of 

 the first toll-bar out of Macclesfield. It is of precisely 



