The Glacial Deposits of West Cumberland. 71 



rupture of the columns there was no marked deviation from the 

 proportionality of strain to stress up to the breaking-point, except in 

 the case of the marble. In crushing, the authors obtained con- 

 siderably lower moduli than those quoted in tables for similar rocks ; 

 and as their experiments were performed upon columns about three 

 times as long as their diameter, they repeated them upon columns 

 of marble varying in length from one half to six times the thickness. 

 The results seemed to show that the short specimens were the 

 weakest; but there was little difference. The authors give the 

 formula? by which they worked out the results of each series of 

 experiments, and bring together the mean results in a tabular form. 



3. "The Glacial Deposits of TVest Cumberland.'^ Bv J. D. 

 Kendall, Esq., C.E., E.G.S. 



The author gave a brief sketch of the physical geography of the 

 district and of the distribution of the more remarkable and easily 

 recognized varieties of rock. The glacial deposits, viz. Boulder- 

 clays, sands, and gravels, occupy mainly the area of low ground 

 skirting the hills, extending upward to a height of about 500 feet 

 above the sea : above that contour-line they only occur in isolated 

 patches or tongue-like prolongations up valleys to elevations oc- 

 casionally of about 1000 feet. The deposits, where fully developed, 

 consist of Upper Boulder-clay, Aliddle Sand and Gravel, and Lower 

 Boulder-clay ; together they sometimes attain a thickness of from 

 100 to about 130 feet. Certain peculiarities in the distribu- 

 tion of the deposits were described. The tripartite arrangement 

 never occurs in the valleys in the mountainous district. Boulder- 

 clays, indeed, sometimes occur here ; but sands are more common. 

 The distribution of the boulders from the more remarkable rocks was 

 described ; tables of these were given, as also of the maximum height 

 above the sea at which each occurs. The origin of the deposits was 

 next discussed. The author is of opinion that the presence in the 

 Lower Boulder- clay of boulders derived from such widely different 

 sources can only be explained by floating ice, but that the cor- 

 respondence of the materials of the clay with rocks in the vicinity 

 shows that glacier-mud produced the finer elements. The Hiddle 

 Sand and Gravel he considers due to denudation of the above 

 materials during a period of emergence. The Upper Boulder-clay 

 he attributes to a second period of submergence corresponding 

 generally in its conditions with the former one. The gravel mounds 

 are probably caused by the stranding of bergs at the end of this 

 period. 



November 16. — R. Etheridge, Esq., E.B.S., President, in the Chair. 



The following communications were read: — 



1. Additional Evidence on the Land Plants from the Pen-y-glog 

 Slate-quarry, near Corwen." By Henry Hicks, Esq., M.D., F.G.S. 



2. "■' Xotes on Prototaxites and PacJiythca from the Denbighshire 

 Grits of Corwen, Xorth "Wales." Bv Principal Dawson, LL.D.. 

 F.E.S., E.G.S. 



