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. 



