Present Aspects of Glacial Geology. 545 



Tracing the extension of the Low-level Marine Boulder-clays 

 and Sands northwards, we find them typically developed at Blackpool 

 in the well-known cliff section first described by Mr. Binney. They 

 can be seen along the coast of Morecambe Bay by Grange, at 

 Rampside opposite Walney Island, and very greatly developed from 

 Ravenglass to St. Bees Head. All the low-level adjoining country 

 inland is occupied with them, and this marine drift, in which shells 

 can be found, is extensive and widespread. 



Turning now to Scotland, we are taught by the very excellent 

 work of Mr. John Smith, of Kilwinning, 1 that a large part of 

 Ayrshire is covered with similar shelly Boulder-clays, and he has 

 traced them up in continuous sections from the sea-level to a height 

 of 1,061 feet at Dippal. These deposits I have myself examined 

 with him, and was much struck by their continuity and regular 

 stratification, no less than with the wonderful preservation of the 

 shell fragments and shells, both often possessing their epidermis 

 unabraded. These beds constitute a really massive formation, often 

 presenting sections 80 feet high through the lateral denudation of 

 the River Ayr. The Boulder-clay in which they are preserved is 

 tough and dry below the weathered surface, so that the shells may 

 by a little trouble be got out of the solid clay ; in fact, Mr. Smith 

 informs me that in all his fifty recorded localities he has obtained 

 his specimens in this way. Though rubbed, polished, and striated 

 shells occur in places, the shells as a rule are much better pre- 

 served than with us. The boulders in the Drift consist to the 

 greater extent of local rocks of the respective watersheds, mixed 

 with some Highland schists. In the valley of the Girvan Water, 

 Loch Doon, granite blocks up to a large size are common, and they 

 also extend further south. 3 



The area worked by Mr. Smith covers tens of square miles, and 

 I have no doubt that the deposits south of his recorded examples 

 are largely of the same nature. In proof of this I may mention 

 that I discovered shelly Boulder-clay containing Loch Doon granite 

 boulders and striated grits in a small exposure in the banks of 

 Byne Hill Burn, about two miles south of Girvan, and 120 feet 

 above the sea-level. The clay was identical in character with that 

 at Muirkirk which I examined with Mr. Smith, and the shells pre- 

 served their epidermis. Mr. J. W. Davies, F.G.S., and I afterwards 

 found fragments of shells at several places in the drift cliffs 

 between Bennan Head and Girvan ; also, at a level of 280 feet 

 we found some shell fragments and a small Turritella in the drift 

 of Byne Hill Burn, south of the place where the shelly Boulder- 

 clay occurs. This is rather remarkable, as Mr. Smith tells me he 

 has found no Turritell in any of his Boulder-clay localities in 

 Ayrshire. 



From my observations I am satisfied that here we have an 



1 " On the Discovery of Marine Shells in the Drift Series at High Levels in 

 Ayrshire" : British Association, Section C, Liverpool Meeting, 1896. 



• The Baron's Stone of Killochan is a well-known example, and, according to 

 Geikie, contains 480 cube feet. 



DECADE IV. VOL. III. — NO. XII. 35 



