Such are some of the more saUent points presented by the 

 glacial deposits of West Cumberland. The deductions to be 

 drawn from them are numerous, and may now be considered. 



3. Deductions. 



Origin of Lower Boulder Clay. The first inference to be drawn 

 from the facts just described is that floating ice seems to have 

 played a most important part in the formation of all the deposits 

 that have been noticed. The mingling of boulders from different 

 sources, sometimes in quite opposite directions, as shewn in 

 Fig. II, cannot be explained in any other way. And since these 

 variously-derived boulders are found side by side in both the 

 Upper- and the Lower Boulder Clay, it follows that floating ice 

 must have been largely concerned in forming these deposits. But 

 a difficulty occurs here. The matrix of the Lower Boulder Clay is 

 clearly local, having, no doubt, been derived from rocks very near 

 where it now lies, whence its sandy character when over-lying 

 rocks that are sandy, 'and its clayey nature when resting on rocks 

 that are argillaceous. Many of the included stones are also of 

 local origin. These results could only have been brought about 

 by glacier-action, so that there is in every deposit of Lower Boulder 

 Clay the results of the action of ice in two very different forms — 

 as icebergs, by which many of the local and far-travelled Ktones 

 were deposited, and as glaciers, which produced the matrix of the 

 deposit ; and also imbedded therein, many of the local boulders, 

 as well as some of the far-travelled ones, the'source of which was in 

 the direction whence the glacier moved. 



Fig. 13, which is a sketch-section of a glacier terminating in the 

 sea, will illustrate the manner in which I conceive these actions to 

 have taken place. 



In its downward motion the glacier would pass into the sea at B, 

 and would move along the sea-bottom until it arrived at C, where 

 the weight of ice in the glacier would equal that of the sea-water 

 displaced. Thence it would leave the sea-bottom and float on 

 toward D, where in all probability it would be broken off into 

 icebergs, and be borne away by currents to other places. The 



