Page:Quarterly Journal of the Geological Society of London, vol. 32.djvu/257

Rh of the great anticlinal range, traversed its eastern and western sides on its march from north to south.

That vast masses of drift deposits overspread the wide plains of Western Lancashire and adjoining counties, extending from the Irish Sea in one unbroken sheet to the slopes of the Pennine Hills, and thence mounting up to higher levels, and penetrating almost every upland valley and mountain-gorge to considerable elevations, is too well known and too generally acknowledged to require any amplification from me on the present occasion.

A great number of facts, and the statements of various authorities as to the altitude of high-level drift on the western slopes of the Pennine chain, indicate a general elevation of from 1100 to 1200 feet, whilst scattered boulders and pebbles of travelled rocks may be detected at various places in the locality some 200 feet in excess of that; and I contend that these more elevated stray boulders and pebbles owed their origin to icebergs during the interglacial period, and not to the period of land ice.

I wish particularly to direct attention to the circumstance of drift having been found at an elevation of 930 feet above sea-level, on the shoulders of the hills on both sides of the southerly termination of the Walsden defile at the summit near Littleborough, whilst all traces of them vanish in a line almost coincident with the watershed of the valley, which has an elevation of 627 feet, beyond which no accumulations of this character are met with in travelling cast for a distance of about 15 miles. The first indication of their presence as a regular bed of drift occurs in the valley of the Calder at North Dean, near Halifax, where, in sinking for the foundations of a railway viaduct, the following section was observed by Mr. James Spencer, of Halifax, to whom I am indebted for the accompanying particulars:—

It is, however, stated that an occasional pebble foreign to the district has been noticed in the bed of the river Calder, a little further to the west than the spot just named.

Close to the railway bridge at Elland, in the bank on the south side of the river Calder, under about 5 feet of sandy loam, a bed of gravel exists, about 4 feet of which is exposed, and which I am informed by Mr. Davis, F.G.S., of Greetland, has been proved by a well-sinking to be from 15 to 20 feet in thickness, in which red