§4 



are indications that the Byle Brook, though now the smaller, played 

 the part of main stream, or divertor, in this change. — 55. 



If it is granted that the union of these two streams took place, 

 originally, south of the chalk ridge, over which the joint river 

 flowed by a single gap, it is easy to follow the Goring case and to 

 suppose that the course of the joint river was for a time blocked by 

 sedentary ice, which piled itself up in the only gorge, and compelled 

 any running water to cut a new channel. 



Are there any moraines in Dorset ? Personally, I think there 

 are, but mostly of the deglaciation or remanie type. Though, 

 indeed, according to the view suggested, most of the morainic stuff 

 would not have been left on the land, but must have been pushed 

 into the sea. 



Mr. Osmond Fisher firmly believes, and in my opinion he is 

 right, that a moraine exists at Chesilton on Portland. I have had, 

 in the past, much correspondence with him on the subject, and have 

 often visited the spot, and now show some of the material. In a 

 letter I received from him last week he permits me to say that he 

 thinks the deposit is a lateral moraine from a glacier descending the 

 valley. The Kimeridge clay, near the governor's house, was 

 squeezed up beneath it by pressure. (See geol. map). 



The accumulation consists of angular rubble in clay, with large 

 subangular blocks of Portland stone and some erratics, among 

 which is a large piece of Hastings-sand rock. 



The clay of this moraine, of which a section appears in the 

 cliff at Chesilton, is quite different from the Kimeridge clay which 

 comes to the surface near the governor's house. Both are shown. 



In this connection it should be noted that, according to Mr. 

 Belt, gravel deposits overlie in Portland remains of Elephas 

 antiquus. — 56. 



The origin of the Chesil Bank is a standing puzzle. It is 

 certain that the pebbles travel from west to east, and the reason 

 why the larger ones travel faster and go farther than the small ones 

 is understood. But how came the bank there at all, and why was 

 not the shingle cast up on the shore ? During heavy gales these 

 pebbles are sometimes greatly displaced, and it can then be seen 

 that they rest upon a bed of clay. That this is Kimeridge clay 

 rather than Oxford clay is probable from the fact of its occurrence 

 at Portland, where Mr. Fisher thinks it was squeezed up by a 

 glacier. 



In Novaya Zemlya, according to Mr. H. W. Fielden, ridges of 

 gravel and mud are pushed up, by glacial action, from the sea 

 bottom so as to form long causeways connecting islands to each 

 other or to the mainland. — 57. 



It has been thought that the bed of the Fleet, of the water 

 between the Chesil Bank and the mainland, was hollowed out by a 

 stream, but the water-shed is too small and the current is too feeble 

 to have produced any scouring effect whatever. 



55 — H. J. Osborne White — P.G.A., xvii., 400-412. 

 56— Q.J.G.S., xxxii., 82, 1876. 

 57— Glac. Mag., v., 95. 



