thickness varies from 40 to 60 feet. An intelligent Scotchman, who had been concerned in well-sinking, informed me that at a depth of 60 feet under this clay the drift was found to consist of a layer of sand with water, a layer of fine bluish clay, a layer of fine gravel, and a layer of sand (middle sand and gravel?). The distinction between this Boulder-clay and pinel was sufficiently manifest. Unlike pinel, which is packed full of stones of all sizes up to a certain diameter, the stones were sparingly distributed through the clay under notice, and, with the exception of the large boulders, a number of the stones taken out of it at random, and gathered into a heap, exhibited a wonderful approximation to uniformity of size. In one heap the average diameter was from 5 to 6 inches. This looked as if the stones, previously assorted, had been brought from a sea-beach by floating ice, and here dropped into the clay as it was accumulating. I was able to trace this clay for a considerable distance N.E. on the Dalton road. What appears to be a continuation of it may be seen between Dalton railway-station and the tunnel, overlying a pebbly gravel.[1]
k. Surface Boulders.—There is a very large boulder of porphyry lying on the surface in a square not far from Barrow railway-station; but it was on Stainton Green, near the centre of the Furness penininsula, that I met with the most extraordinary array of enormous boulders in close proximity I have anywhere seen remote from a hill-side from which they could have fallen, and in a situation where no valley-glacier could have left them. The largest was about 18 X 12 X 4; but Mr. Bolton (a meritorious local geologist) informed me that three or four stones, at least twice as large, had been blasted and used for building. The lower part of the boulders was imbedded in ochreous drift. They were more or less rounded and smoothly sculptured, the sculpturing, as before stated, running down under the stones. In some places they were polished. Here and there smooth basins and furrows had evidently been ground out. One curvilinear channel, not only smooth but almost polished, was two feet deep. On one side of it, and opening downwards, a smooth circular small hole presented a facsimile of a part of a Pholas-burrow. The possible derivation of these boulders could easily be traced; for a limestone cliff consisting of rounded, basined, and channelled blocks might be seen three or four hundred yards off, from which they were probably floated by ice.
1. Sections obtained by borings near Ireleth.—As a means of ascertaining the succession of deposits, bore-holes are seldom to be relied on; but, in connexion with the question of the triplex division of the drifts in Furness, it may be important to give a section of one
- ↑ I had little time to notice the Postglacial deposits of the Furness peninsula. They consist principally of a bluish or greyish warp or clay, which partly fills up the low-level valleys, and runs round knolls of glacial drift—and of a formation, more or less consolidated, of sand and shells, which I have reason to believe cannot be referred to any particular period, though it is certainly newer than the Upper Boulder-clay, and in many places older than the recent beach-sand and shingle. I have only seen it on the beach, at the mouth of a brook, near Seawood.
