132 ON THE DELFT-BEDS OF THE N.W. OF ENGLAND AND N. WALES. 



conclusions. Although not peculiar to such conditions, they are 

 frequently met with in situations more or less brackish *. 



The Boulder-clays differ from our Scottish Boulder-clay (Till) by 

 being fossiliferous and intercalated with fossiliferous beds of sand 

 and gravel. 



A fossiliferous section of Boulder-clay that I examined at Knock- 

 burn, near Belfast, was much like that at Bootle, being fossiliferous 

 and intercalated with beds of various composition. 



EXPLANATION OF PLATE V. 



Map of the Basin of the River Mersey, and of part of that of the Dee, to show 

 the relation batween the Drift and the Rock- structure of the Basins. 



Discussion. 



The Chairman (Dr. J. Gwyn Jeffreys) said that having examined 

 probably all the Post-tertiary shells which had been recorded from 

 the extensive district under consideration, he had come to the con- 

 clusion that none of them were Arctic, but that nearly all were 

 local, with a remarkable admixture of both northern and southern 

 forms. The most peculiarly northern species is Astarte borealis, 

 which is not now found living further south than Kiel Bay. The 

 Foraminifera noticed in the paper are all local. 



Prof. Prestwich asked how river-action could have taken place 

 during the great submergence supposed by the author. He re- 

 marked on the great value of the evidence which the sections in 

 this paper afforded of the excavation of many river-valleys in 

 preglacial times, and thus of the higher position of the land. 



Mr. Bauerman remarked on the value of the work done by Mr. 

 Mellard Keade in watching excavations going on during many years 

 — excavations which would soon be filled in or obscured. He re- 

 marked that the fragment of chalk exhibited was more like the 

 Antrim than the English chalk. 



Prof. Bom Dawkins said that fragments of chalk undistinguish- 

 able from that of Antrim are found in Lancashire and as far to the 

 south-east as Ironbridge on the banks of the Severn. 



The Author thought that the non-arctic character of the boulder- 

 clay shells was accounted for by the fact that the severest cold had 

 passed away when they were deposited. At Widnes the river- valley 

 was excavated 140 feet below the present sea-level. 



* This silt is probably the equivalent of the beds underlying the great peat- 

 bed, which the author has named the Formby and Leasowe marine bed. See " Post- 

 glacial Geology of Lancashire," Proc. of Liverpool Geol. Soc, Session 1871-72. 



