52 [Pi'oC' B. N. F. C, 



markings, either faint or strong, can be seen. Mr. Stewart 

 next described the Boulder Clay occurring in this district as a 

 marine shell-bearing deposit, of such distinct and remarkable 

 character that it has no parallel in the sedimentary beds of any 

 other age. The descriptions of it given by various geologists 

 were cited, and these accounts agreeing very well, and giving a 

 fair statement of the physical characters and structure, might 

 be accepted as, on the whole, correctly representing the deposit 

 as it occurs here. As to the origin of the Boulder Clay, it is 

 commonly attributed to the action of land ice, in the form of a 

 great Polar ice-cap. There are, however, two fatal objections 

 to the land ice theory : First — no clay could be formed beneath 

 a mass of moving ice, the rock would be swept quite bare : 

 Second — the marine shells embedded in the clay, many of 

 which cannot be suspected of being either derivative or trans- 

 ported, render it impossible to suppose that the beds are other 

 than marine. Portlock stated the true nature of these glacial 

 clays, but his account being either overlooked or ignored, it was 

 time to put it on record, in the most decided manner, that the 

 Boulder Clay of the North-East of Ireland is a marine sedimen- 

 tary rock, the materials composing it having been deposited in 

 the sea during the glacial epoch. It has no doubt been rapidly 

 accumulated, and its components but slightly assorted by cur- 

 rents ot water, but, nevertheless, unquestionably marine. Lists 

 of the Boulder Clay shells and foraminifera will shortly be 

 published. Mr. Stewart concluded by referring to the theory pro- 

 pounded by the Rev. Maxwell Close, and advocated by Professor 

 liull — that the glaciation of Ireland resulted from a central 

 snowfield, stretching from Antrim to Galway. This centrifugal 

 theory was highly improbable, and not justified by such 

 inferences in respect of the ice movement as we can draw from 

 the striated rocks and the boulders in the till. 



An animated discussion followed the reading of the paper. 

 Regarding the origin of the clay, the various theories afloat 

 seemed each to have a supporter at the meeting. The reader was, 

 however, strongly supported — those members who had closely 



