Reports and Proceedings — Geological Society of Lo)idon. 279 



confluence of Lake District and Irish Sea ice, the summit of Black 

 Combe (1,969 feet) being overridden by ice which was comparatively 

 clean. 



The Lake District ice travelled from the Broughton Yalley, the 

 Duddon Valley and high ground to the west, and from Eskdale. 

 jS^ear the coastline the ovez'mastering pressure of the Irish Sea 

 glacier diverted the seaward flow of the Lake District ice to the south 

 or south-east. 



The deposits of the Lake District ice are briefly described, and 

 a more detailed description is given of the deposits of the Irish Sea 

 ice which ai'e exposed in the sea-cliffs of the coastal plain. The 

 distribution of Scottish boulders is also discussed. 



In the Lower Boulder-clay of the westward mountain slopes 

 (the ground-moraine of combined Lake District and Irish Sea ice) 

 there is evidence both of the interweaving of drifts of distant and 

 strictly local origin, and of a certain amount of movement of ice 

 inland. 



Phenomena which occurred during the withdrawal of the ice are 

 next described under the following heads: — 



(1) Moraines and trails of hoidders. 



(2) Marginal channels and associated sands and gravels. — The trend 

 of these channels is, in the best examples, parallel to the coast and 

 nearly at right angles to the present drainage-lines. In some cases 

 the channels were carriers of the ordinary marginal drainage of the 

 ice-sheet, in other cases they were cut by overflow waters from 

 impounded lakelets. Before the cutting of the channels between 

 Eskdale and Bootle the ice overrode a series of sands and gravels 

 formed, chiefly as a marginal outwash-fan, at a slightly earlier date. 



(3) Sand and gravel of the plain. — These deposits are considered to 

 have been accumulated after the formation of the channels near Bootle, 

 the material being in the main deposited in embay ments of the margin 

 of the Irish Sea ice. 



(4) The Whicham Valley and D^iddon Estuary Lalces. — Sand and 

 gravel was also accumulated at the extremities of ice-lobes which 

 were thrust into the mouths of valleys, so that the normal drainage of 

 these valleys was obstructed. The ice-dammed Whicham Valley Lake 

 is described in detail; it drained at first into the Duddon Estuary by 

 the Gill Scar channel, but afterwards through the obstructing barrier — 

 reversing the flow of water. 



The Upper Boulder-clay is then briefly discussed, and some account 

 is given of late corrie glaciation. 



In conclusion, certain hanging valleys are shown to be due to the 

 over-steepening of hill-slopes, or over-deepening of main valleys during 

 the maximum glaciation. 



2. "The Older Palaeozoic Succession of the Duddon Estuary." 

 By John Frederick IS'orman Green, B.A., F.G.S. 



The Lower Palaeozoic geology of the estuary of the Duddon, which 

 separates Cumberland and Lancashire, has been little studied, but 

 is of especial interest, because the (?) Skiddaw Slate, Volcanic Series, 

 and Coniston Limestone Series are in proximity along an outcrop 



