60 Rev. J. Clifton Ward — Geology of the Lake District. 



against the eastern end of the channel, and much of it might have 

 been rolled well into or through the strait. The subsequent great 

 deepening and widening of this channel to form the present broad 

 valley may easily have removed all traces of the further westerly 

 extension of the conglomerate. (The base of the conglomerate at 

 Mell Fell stands at about the 1000 ft. level.) This might account 

 for the great local thickening of the conglomerate along an east and 

 west line, although of course its present distribution in the form of 

 a band, two miles wide and some five in length, is due partly to the 

 overlap of the limestone on the north and east, and in the south its 

 boundary appears to be mostly a faulted one. 



I should be inclined to think that on the whole it was most likely 

 that the drift of Upper Silurian pebbles was from the south, round 

 the skirts of the land-nucleus by Shap and Bampton, until, the 

 current being deflected up the eastern end of the early Keswick Vale 

 strait, the material might be there banked up and prevented from 

 being carried further north, partly by the set westwards up channel, 

 and partly, perhaps, by more or less of a bank on the north side of 

 the mouth of the strait. Certain it is that north of the present line 

 of railway (between Keswick and Penrith) the conglomerate is 

 almost entirely absent. 



My former supposition as to the land-nucleus being covered with an 

 ice-sheet I regard as very doubtful, but one cannot but be surprised at 

 the scarcity of pebbles derived from the Yolcanic series, although, as 

 I have remarked, they are more numerous at some spots than others. 

 It may have been that cold conditions prevailed, as rather indicated 

 by the character of some of the stones in the conglomerate (the 

 apparently flattened and scratched stones, and the large and more 

 angular blocks) ; but if cold prevailed, and ice and snow were at 

 work upon the land, one might have expected to see more indications 

 of their action in the shore deposits. There is, however, another 

 fact which rather strongly militates against the idea of a glacial 

 climate having prevailed at this time. North of Carlisle, all along 

 and over the border, there occurs a great development of the 

 Calciferous Sandstone Series, consisting of many thousands of feet 

 of beds below the true Limestone Series of Cumberland, as 

 developed east of the Lake District. This great thickness, gritty 

 sandstones in the upper part, and thin limestones and shales with 

 occasional coal-seams in the lower part, must, one would suppose, 

 have been in course of deposition during the period of formation of 

 the so-called Basement Conglomerate, and, perhaps, long anterior to 

 the commencement of its formation. Now these beds show no signs 

 of glacial conditions, the lower part (thin limestones — with ordinary 

 Carboniferous Limestone fossils, — shales, and a few coals) indicates 

 similar conditions to those prevailing during the rest of the Carboni- 

 ferous — sometimes marine, sometimes fresh-water, sometimes terres- 

 trial — and the upper part consists mostly of thick gritty sandstones 

 containing thin calcareous bands, and occasional coal-seams with shale. 

 Hence we must suppose either that (1) previous to and during the for- 

 mation of the Mell Fell Conglomerate, rocks of a Carboniferous type 



