Geological Society of London. 517 



9. " On some important Facts connected with the Boulders and 

 Drifts of the Eden Valley, and their bearing on the Theory of a 

 Melting Ice-sheet charged throughout with Kock-fragments." By 

 D. Mackintosh, Esq., F.G-.S. 



In this paper the main object of the author is to defend generally 

 received opinions, especially as regards the great glacial submergence, 

 in opposition to the theory announced in the Quart. Journ. Geol. 

 Soc. for last February (vol. xxxi. p. 55). He brings forward a 

 number of facts and considerations, founded on repeated observations, 

 to show that the dispersion of Criffell granite-boulders is so inter- 

 woven with that of boulders of porphyry and syenite from the Lake- 

 district as to be incompatible with the theory of transportation by 

 currents of land-ice ; and that the limitation of Criffell boulders 

 along the S.E. border of the plain of Cumberland to about 400 feet 

 above the sea-level is inconsistent with the idea of a boulder-charged 

 ice-current 2400 feet in thickness. He likewise calls attention to 

 the interweaving of Criffell with Shapfell granite in the lower part 

 of the Eden Valley at too acute an angle to be satisfactorily explained 

 by upper and under currents of land-ice. He remarks that Mr. 

 Goodchild has not taken into account the dispersion of numerous 

 Shap-granite boulders over ground at least 1300 feet above the sea- 

 level as far south as Milnethorpe. He defends the idea of a special 

 dispersion of surface-blocks of Shap granite, and believes that the 

 limited altitude they have reached on Stainmoor is opposed to the 

 theory of a boulder-charged ice-current 2300 feet in thickness, while 

 an ice-current only 1500 feet in thickness on Stainmoor could not 

 have persisted in carrying the boulders over opposing eminences as 

 far as Bridlington on the Yorkshire coast. The author still further 

 believes that the sudden disappearance of the ice- sheet can be better 

 explained by the encroachment of the sea than by the subaerial 

 melting of the ice. But his main argument against the theory of 

 land-ice " charged throughout with rock-fragments of all sizes " is 

 derived from the purity of the interiors of existing ice-sheets ; and 

 he quotes Professor Wyville Thomson in support of his statements. 



10. "Observations on the unequal distribution of Drift on oppo- 

 site sides of the Pennine chain, in the country about the source of 

 the river Calder, with suggestions as to the causes which led to that 

 result, together with some notices on the High-level Drift in the 

 upper part of the Valley of the river Irwell." By John Aitken, 

 Esq., F.G.S. 



The author, in calling attention to the unequal distribution of the 

 drift on the opposite side of the Pennine chain in this district, 

 points out that on the western side of that range an extensive series 

 of drift -deposits is found, spreading over the great plains of Lan- 

 cashire and Cheshire down to the Irish Sea. It also occurs on the 

 west flanks of the chain at elevations of from 1100 to 1200 feet, 

 thus rising several hundred feet above the watersheds of some of 

 the valleys penetrating that elevated region. On the eastern side, 

 however, there is, with one or two slight exceptions, an entire 

 absence of such accumulations, even in the most sheltered and 



