C. E. Be Ranee — Olaciation of N.W. of England. 415 



"to come within the influence of the Gulf Stream, it is rapidly- 

 dissolved, that is, during June, July, August." After this month the 

 arctic currrent bears back the remnant of the Gulf Stream, and the 

 "polar ice, aided by the increasing cold, comes down in such 

 quantities as to defy the efforts of the now vanquished Gulf Stream 

 to dissolve it." It sweeps round the coast, meets another polar 

 current from the other side, and wraps the island during the winter 

 in an impenetrable barrier of ice. Regarding the warm episode in 

 the Glacial epoch, during which the Middle Sand was formed, as an 

 extended summer, it is easy to explain the fact, that though both of 

 the Boulder-clays contain northern erratics, yet in the Middle Sand 

 fossils and pebbles from the south often occur. Thus in 1861 1 found 

 in the sands of Leamington, in Warwickshire, Corals from the Lias 

 of Cheltenham, Pectens and other fossils from the Eed Crag, and a 

 Nautilus from the London Clay. And in the neighbourhood of Crewe 

 Mr. Taylor, F.G.S., has recorded the presence of a great number of 

 chalk flints, though possibly these., like those from Blackpool, may 

 come from Antrim. 



In Lancashire the Middle Sands are invariably current-bedded to 

 the south-east; and as I believe that they were thrown down during 

 the floio-tide, it follows that it moved from the north-west, but in the 

 south it may possibly have moved in the opposite direction, the 

 meeting of the tides being then in Warwickshire, instead of in 

 Morecambe Bay, as now. In the Upper Boulder-clay the north-west 

 currents no doubt moved nearly as far south as the Thames. 



It is clear from the descriptions of Drs. Brown, Sutherland, Kane, 

 Eink, and Lament, and other arctic travellers, that land-ice can make 

 its way for a considerable distance into the sea, scratching and 

 striating the rock-surface, and forming true moraine mounds, not 

 only in the sea, but rising above it, forming islands, the sea-margins 

 of which being exposed to the waves will be slightly denuded, and 

 re-deposited at lower levels ; in fact, the moraine mound may be 

 faced, so to speak, with a marine deposit, composed of re-assorted 

 land-ice debris. And, further, that these marine beds fill up and 

 render seas shallow in the neighbourhood of the embouchure of large 

 glaciers, forming Boulder-clay similar to that of the north-west of 

 England, lying upon and graduating into moraine matter, and 

 resting upon glaciated rock-surfaces, such as we find in the Lake 

 District ; and it is clear that, on the retreat of the glacier and the 

 subsidence of the sea-bottom, the sea-belt occupying the space 

 between the moraine island and the land would also become 

 gradually filled up with marine deposits. 



In the Upper and Lower Boulder-clays, as I have endeavoured to 

 show,^ the included stones and clayey matrix are almost invariably 

 from different sources, formations, and localities. In the Middle 

 Sand, on the contrary, the pebbles are composed of fragments of the 

 neighbouring and surrounding rocks, and where it rests on the 

 Lower Boulder-clay, of such erratic pebbles as may occur in that 

 deposit at the particular locality. 



1 Quart. Journ. Geol. Soc, vol. xzvii., *' On tke Glacial Phenomena, etc' 



