172 PHYSICAL GEOLOGY. 



2. DENUDATION; GLACIAL PHENOMENA. 



Agassiz, Louis [the late]. Formation de la vallee de TAmazone. 



La thcorie glaciaire, &c. Bev. Sci. pp. 868-872, 892-897. 

 xi report of part of a course of lectures at New York on the forma- 

 tion of the Amazon valley, the Glacial theory, &c. 



Bachmann-, Prof. J. Neuentdeckte Pdesentopfe in der Gegend von 

 Bern. [Newly discovered Giant Kettles in the neighbourhood of 

 Bern.] Berner Mittheilungen, p. 136. 



Bell, Dugald. Notes on the Glaciation of the West of Scotland, 



with reference to some recently observed instances of Cross- 



striation. Trans. Gcol. Soc. Glasgow, vol. iv. part 3, pp. 300- 



310. 



After pointing out that the general glaciation of the Forth and 



Clyde valley is from W. to E.. (or N.W. to S.E.), the author calls 



. attention to a section at Possil, which shows two sets of stria3 — one 



from the usual quarter, and the other from nearly due E. The latter 



is considered to be the newer, and is ascribed to land-ice, which, as it 



shrank in bulk, instead of remaining one continuous sheet, would in 



places form separate streams. Thus the changed direction of striae is 



explained by the formation of two main inflows of ice towards the 



central part of the valley — one past the S.W. or Kilpatrick end of the 



range, and the other past the N.E. or Strathblane end. If the one 



shrank in bulk more than the other, a change in the direction of the 



striaB they were producing would ensue. G. A. L. 



Belt, Thomas. An Examination of the Theories that have been 

 propounded to account for the climate of the Glacial Period. Quart. 

 Journ. Sci. no. xliv. p. 421. 



Sir C. Lyell's and Mr. CroU's theories are rejected, and a change in 

 the obliquity of the ecliptic is propounded as the producing cause. 

 Increase of obliquity will cause a simultaneous accumulation of ice and 

 enow round each pole : the water thus withdrawn from the sea will 

 lower its level ; the melting of the ice will raise the sea-level. The 

 author attributes many oscillations of the sea-level to this cause 

 rather than to upheaval and depression of the land. The polar accu- 

 mulations of ice alter the figure of the earth, and tend to set up a series 

 of strains in the crust ; on the melting of the ice converse changes are 

 brought about ; and the author suggests that volcanic phenomena may 

 be due to the action of these forces. By decrease of obliquity a 

 warmer temperature would be produced ; and this is perhaps the origin 

 of the warm climate of early Tertiary times and of the Arctic regions 

 during Miocene times. A. H. G. 



Bou£, A. Mittheilungen aus einem Schreiben der Herrn E. CoUomb 

 in Paris. [Communications from a letter of M. E. Collomb.] 

 Yerh. k.-k. geol. Keichs. pp. 118, 119. 



