PHYSICAL GEOLOGY. 181 



Brann, Alexander. The Glacial Epoch of our Globe. In vol. i. of 

 " Half-hour Kecreations in Natural History " of Estes and Laureat. 



B0St07l. 



Brown, Dr. R. The Arctic Expedition : its Scientific Aims. Pop, 



Sci. Rev. vol. xiv. pp. 15-1:-163. 

 Notices the chief geological questions upon which light may be 

 thrown by the expedition. 



Carpenter, Dr. W. B. On the Glacial Epoch. Coll. Giuird, 



vol. xxix. p. 59. 

 Abstract of Swiney Lecture, delivered Jan. 1, 1875. 



Dakyns, J. R. The Sediment Theory of Drift. Geol. Mag. dec. ii. 

 vol. ii. pp. 168-172. 



Kemarks that Mr. Goodchild's theory explains how the glaciers 

 which scored the rocks also carried and afterwards deposited the debris 

 forming the Boulder Clay ; but it is difficult to understand whence the 

 stones were derived if the whole country were covered with ice. The 

 sediment theory does not explain why drift is sometimes local in its 

 distribution, nor the occurrence of wide-spread deposits of stratified 

 sand and gravel with an overlying Boulder Clay ; nor, again, the dif- 

 ference between Eskars and the Middle Sands ; for according to the 

 theory both are formed in the same way. The stones in the drift 

 of the Yorkshire dales are all local. The ice seems to have radiated 

 from Bar Fell ; but the summit of this fell is grooved ; and as this can- 

 not have been done by ice at the point of radiation, it probably 

 points to submergence to this amount (2200 feet) and the action of ice- 

 bergs. Refers to Mr. Goodchild's theory of cross-currents in the ice, 

 and suggests that the application of this idea involves the fallacy of 

 perpetual motion. W. T. 



D[ana], J. D. Notice of Mr. CroU's paper * on the Submergence 



during the Glacial period.' Amer. Joum. ser. 3, vol. ix. pp. 315, 



316. 



Notes that *' the facts from Eastern North America do not appear to 



favour Mr. Croll's conclusions." G. A. L. 



. Notice of Mr. Belt's paper entitled ' An examination of the 



Theories that have been proposed to account for the Climate of 

 the Glacial Period.' Amer. Joum. ser. 3, vol. ix. pp. 313-315. 

 Criticises Mr. Belt's theory of the lowering of the sea-level to the 

 extent of 2000 feet. The Atlantic border shows no evidence of this. 

 Notes that Mr. Belt has not included among possible sources of cold 

 the exclusion of the Gulf Stream from the Arctic regions by a rise of 

 the land there. G. A. L, 



Dawson, Principal J. W. Marine Boulder Clay, and other Deposits. 



Is^ature^ vol. xi. p. 306. 

 The ' Challenger ' observations show that the deposition of mud and 

 sand with stones dropped by floating ice is now going on so rapidly in 



