Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/851

Rh AROUND THE ESTUARY OF THE DEE. 739 Supplementary Notes. Sept. 1877. — Since this paper was written I have again examined the Dawpool cliffs, accompanied by Mr. Shone, F.G.S. Fresh clay- slips have revealed a considerable thickness of normal middle sand extending horizontally for several hundred yards. I have likewise examined a newly cut section (Aug. 1, 1877), nearly 200 yards long, at Egremont, which shows a striking difference between the lower and upper clays. The columnar structure of the latter is here strikingly developed ; and the greyish-white faces of its fractures make it appear almost like a range of chalk cliffs. The sand at its base is evidently on the same horizon as the thick bed at Codling Gap, some distance to the south. The surface of this bed presents the appearance of having been finely ripple-marked immediately before the tranquil deposition of an inch in thickness of leaf-like laminae which, within the vertical space of a few inches, graduate into the typical upper clay. Similarly marked junctions may be seen near Chester. The last time I visited the Bootle new dock- sections I particularly noticed that the striae on the flattened sur- faces of the large boulders (nearly all of which are so-called green- stone) ran in various directions without any special relation to the longer axes of the stones. Having been unable to trace these (and kindred boulders at Dawpool) to the Lake-district, I sent specimens to Mr. James Geikie, F.R.S., who, along with Mr. Home, recognized them as having come from the outskirts of Criffell Mountain. Professor Hull has enabled me to trace a large boulder of calcare- ous conglomerate (which may be seen in an upper-clay brick-pit south of Wrexham) to the lower Keuper beds of the Delamere or Peckforton hills, from which its course must have been nearly at right angles to that of the Eskdale granite with which, in the brick- pit, it is associated.