182 PHTSICAL GEOLOGY. 



the Southern Ocean, as to obliterate all traces of organic slime, and 

 that in certain deep-water areas the excess of carbonic acid may 

 remove the remains of calcareous organisms. Believes the Boulder 

 Clays of N. America to have had a similar origin. C. E. R. 



Ekman, F. L. Om do stromningar som uppsta i narheten af flod- 

 mynningar : ett bidrag till kannedomen om hafs-strommarnes 

 natur. [Currents in the neighbourhood of river-mouths : a con- 

 tribution to the knowledge of the nature of the currents in the 

 sea.] Q^fvers. h. Svem^lca Vet. Akacl. Forhandl. no. 7, pp. 43- 

 134, with a hydrographical map. 



Gaudard, Jules. Notes on the Consolidation of Earthworks. Trans- 

 lated from the Erench by Jas. Dredge. Proc. Inst. Civ. Eng. 

 vol. xxxix. pp. 218-247 ; 44 woodcuts. 



Notes the influence of springs, decomposition of iron-pyrites, frost, 

 &c. The Physical Causes of Landslips described on pp. 223-227. 



Gilbert, G. E. Wind-drift Erosion. Amer. Journ. ser. 3, vol. ix. 



pp. 151, 152. 

 Note claiming priority of observation of the effects of erosion by sand 

 in the Western Territories for Prof. W. P. Blake, 1855. G. A. L. 



Goodchild, J. G. Glacial Erosion. Geol. Mag. dec. ii. vol. ii. 

 pp. 323-328, 356-362. 



Gives reasons for concluding that the varying rates of destructibility 

 of the Carboniferous rocks in the Yorkshire Dales, under ordinary 

 Bubaerial conditions, would give rise to minor details of surface con- 

 figuration different from those that would be left after long exposure to 

 the abrading action of ice. Considers that, as some of the more 

 prominent features consist of rocks that are least able to withstand the 

 attacks of subaerial erosion, and are at the same time most capable of 

 resisting erosion by mechanical means, they must be due to the modi- 

 fication of a preglacially weathered surface by the long-continued 

 erosion of the ice-sheet. J. G. G. 



On the Origin of Coums. Geol. Mag. dec. ii. vol. ii. pp. 486, 



487._ 



Assuming that certain terraces in the Yorkshire Dales have had a 

 glacial origin, points out that the transition in form from these to semi- 

 circular recesses like cirques and corries leads to the belief that these 

 recesses have had a glacial origin also. Tlieir resemblance in form and 

 position to the concavities formed by streams under like circumstances 

 points to a similarity of origin ; and the author concludes that, as the 

 analogy between the laws of motion of a glacier and that of a river 

 has been proved to be almost complete, under the extreme conditions 

 that obtained during the Ice- sheet period the analogy was complete in 

 every respect, and that the epums or cirques are really gigantic potholes 

 produced by the slow but long-continued eddying of the ice- sheet. 



J. G. G. 



