GEOLOGICAL PAPERS AT THE BRITISH ASSOCIATION. 293 



of Extra -Morainic Boulder Clay' (these were, no doubt, the most 

 original in idea and the boldest in theory of all the papers read 

 before the section. The Professor, although from Philadelphia, had 

 traversed and studied the whole of the North and East of England 

 in detail for this paper. He argued that every glacier at the time of 

 its greatest extension is bounded and limited by a terminal moraine. 

 The glaciers which once covered Northern England were studied in 

 detail, beginning with the East of England, and the North Sea glacier, 

 the Wensleydale glacier, the Stainmoor glacier, the Aire glacier, and 

 others were distinguished by characteristic boulders, and said to 

 be defined by well-marked moraines. The minuteness of detail 

 respecting Yorkshire and Lancashire, and the information given, was 

 surprisingly great. In the second paper the Professor advanced from 

 one argument to another until he announced his conclusion that the 

 glacial phenomena of England are due neither to a universal ice-cap 

 nor to a marine submergence, but to a number of glaciers bordered 

 by freshwater lakes — that is, the glacier wall dammed up the rivers 

 from the great watersheds of the west, constituting thus great fresh- 

 water lakes. These papers were stoutly controverted in discussion by 

 numerous eminent English glacialists, one gentleman dogmatically 

 denying any indication of a terminal moraine in the neighbourhood of 

 Manchester, whereupon Prof Lewis smilingly arranged forthwith an 

 excursion to point it out !); J. W. Davis, on 'An Ancient Sea-beach near 

 Bridlington, containing Mammalian Remains ' (this valuable investi- 

 gation, instituted by the Yorkshire Geological Society, received a 

 grant of jQ2o from the British Association for the further examination 

 of this section) ; Prof. Boyd Dawkins, on ' The Schists of the Isle of 

 Man'; Prof. Lebour, on 'Thinolite and Jarrowite' (the latter, a new 

 mineral found in the muds of the river Tyne) ; Thomas Ward, on 

 'The History and Cause of the Subsidences at Northwich and its 

 neighbourhood in the Salt Districts of Cheshire ' (after giving the 

 geology of the district and the history and progress of the salt trade, 

 he related the cause of the subsidences, the continual removal of the 

 beds of rock salt by solution and pumping, when the overlying 

 strata suddenly fall into the cavities thus made) ; Prof. W. C. 

 Williamson, F.R.S. (in the absence of Mr. Cash), 'Report on the 

 Carboniferous Flora of Halifax ' (it was stated that during the last 

 year the researches had been less fruitful than usual in the neighbour- 

 hood of Halifax, but had been more successful in the surrounding 

 districts. The most notable result had been in materially enabling 

 them to determine with absolute certainty the fructification of the 

 calamites) ; C. E. de Ranee, ' Report on the underground waters in 

 thePermeable Formations of England'; Prof. J. F. Blake, 'Description 



Oct. 1887. 



