414 C. E. Be Ranee — Glaciation of N. W. of England. 



striated under the sea by projecting glaciers, or by icebergs, and 

 afterwards covered with marine drift, will retain their striations on 

 elevation above the sea, and the glaciated surface be preserved on 

 passing the tidal zone, provided they are elevated above it, at a 

 greater rate than the waves can denude, the precise thickness of 

 overlying and protecting Boulder-drifts ; but this marine drift will 

 have been deposited during either subsidence or entire cessation 

 of movement of the sea-bottom. In Lancashire, it is often a great 

 thickness. I have had a recent instance, north of Wigan, of its 

 attaining a depth of 180 feet in a flat country. 



I, therefore, for these reasons, cannot admit Mr. Mackintosh's 

 dictum, " that it is a fundamental principle in geology, that strise 

 are preserved in areas of depression," nor its converse, " in areas 

 of elevation ; " and, further, I believe that it is the former alone, 

 almost without exception, that are areas of deposition of true sedi- 

 mentary rocks. Mr. Darwin, F.E.S., states on this point, "I am 

 convinced that nearly all our ancient formations, which are throughout 

 the greater part of their thickness rich in fossils, have thus been 

 formed during subsidence. Since publishing my views on this 

 subject in 1845, I have watched the progress of Geology, and have 

 been surprised to note how author after author, in treating of this or 

 that great formation, has come to the conclusion that it was accumu- 

 lated during subsidence." ^ And he further shows that, though vast 

 quantities of sediment may enter a sea, from muddy rivers and 

 eroded coasts, around a rising continent, and littoral and sub-littoral 

 deposits may be formed, these must be infallibly gradually worn and 

 denuded away, as they are successively brought up to the action of 

 the waves by the slow and gradual rise of the land. 



If the sands and shingle occurring between the two marine 

 Boulder-clays have been deposited as sand-banks, similar to those 

 now found in the estuaries of rivers, and on coasts with small 

 soundings, — -as I have endeavoured to show in my paper on the 

 ''Glacial Phenomena of Western Lancashire and Cheshire,"^ and 

 which Mr. Mackintosh does not appear to question, — it appears to me 

 to be impossible that they could have been thrown down, as he 

 states, " during elevation," for each sandbank as it rose would be 

 exposed to the action of the breakers, and, at the least, be denuded and 

 re-deposited as a flat surface ; while everywhere, from Carnarvonshire 

 to Cumberland, I have observed the surface of these sands to have a 

 curved, flowing outline, the hollows of which have since been filled 

 in with Upper Boulder-clay. 



The observations of Mr. Lament, F.G.S., in the seas of Spitzbergen, 

 on the changes of direction in the currents of the sea at different 

 times of the year, have an important bearing on many of the 

 phenomena of the Glacial drift. Thus, he shows that the Gulf Stream 

 has little or no influence to the north and east of Black Point 

 (Spitzbergen) and the Thousand Isles, as the ice is always travelling 

 south-west, but immediately it is driven past that promontory, so as 



1 « Origin of Species," 5th ed., pp. 358-9. 



2 Quart. Journ. Geol. Soc, vol. xxvii. 



