Page:The Geologist, volume 5.djvu/90

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70
THE GEOLOGIST.

Mr. Edward Hull, B.A., called attention to instances of glacial striations recently discovered by Mr. G. H. Morton, at Liverpool. During a recent visit to that town in connexion with his duties on the Geological Survey, Mr. Hull was kindly conducted by Mr. Morton to the spots where the striæ are visible. One of these is at the south, the other at the north side of the town, and at the latter the extent of surface exposed is several hundred square yards. The rock-surfaces had been protected by a thick coating of boulder clay, which has been removed for brick-making. It is owing to the protection thus afforded to the rock that the striations are preserved in all their original freshness. The rock belongs to the New Red Sandstone, and is a moderately hard reddish-brown and yellowish building-stone. There are two systems of striæ, the primary one ranging N.N.W., the secondary nearly east and west. Of tiie latter, the markings are comparatively unimportant, but are very clear and sharp. The primary striæ run in remarkably straight lines—in the form of deep groovings and scratches, and the whole surface of the sandstone is worn down to one uniform gently-sloping plane.

It appeared evident, from the directions of the striæ, that they had been produced by icebergs coming from the north, in all probability from the Cumberland mountains, where glaciers are known to have existed during the period of the boulder clay, or rather earlier. The secondary groovings might have been produced by bergs coming from North Wales, but this appeared very problematical. The interest attached to these cases of glaciation was stated to arise from their position at so great a distance from the Cumberland range. In the immediate neighbourhood of these mountains, as also in that of North Wales, ice-moulded surfaces have frequently been observed, but never before on the New Red Sandstone of Lancashire or Cheshire.

Mr. E. W. Binney referred to the existence of similar striations on the Carboniferous limestone of Great Orme's Head, where the groovings were found to range northward, or outwards from the mountains of the interior. He also noticed the distribution of the Shap granite, blocks of which he had lately seen on the high Silurian and Carboniferous ranges to the south and south-east of Shap Fell.

Mr. Brockbank stated that, on the high lands of Yorkshire and Derbyshire, he had observed erratic blocks which could be traced to their northern sources.

Mr. Hull said, it had been shown, by a large number of facts, that the direction of the erratic blocks of the Drift period was from north to south, so that there must have been some predominating influence in operation, either prevalent winds, or, more probably, oceanic currents, tending to impel southward the icebergs and rafts which were the vehicles for the transportation of the erratic boulders and pebbles.

Geological Society of London.—January 8, 1862.—Sir C. Lyell in the chair. The following communications were read:—1. "On the Carboniferous Limestone of Oreton and Farlow, Clee Hills, Shropshire." By Professor John Morris, V.P.G.S., and George E. Roberts, Esq. With a Note upon a new species of Perichthys, by Sir P. de M. G. Egerton, Bart., M.P., F.G.S. The rocks described in this paper are a series of thin beds of limestone and sandstone lying between the Old Red Sandstone of South Shropshire and the Millstone Grit which forms the basement of the Titterstone Clee coal-field. In consequence of the opening of new quarries and the cutting of a roadway through the Farlow ridge transversely to the strike of these deposits, the authors were enabled to add somewhat to the description of the locality given in 'The Silurian System.' The series of de-