534 REV. R. B. WATSON ON THE GREAT DRIFT- BEDS WITH SHELLS 



from its rounded form, but its whole exposed surface is utterly shattered, Avhile 

 its junction with the overlying clay beds is entirely concealed by debris. (Plate 

 XXII. fig. 13.) Resting directly on it, is a confused dark-coloured bed of gravelly 

 clay, with large angular stones crushed rather than ground, some of them striated. 

 In this, a year ago, I found quantities of heather-stalks, but this spring, on revisit- 

 ing the place, I found it a good deal more concealed by debris, and I could only 

 find one bit of heather-stalk about an inch long, which I fairly dug out of the clay 

 among the hard pressed fragments of stone. The discoloration of the bed, Avhich 

 is very marked, may be partly due to the vegetable matter, but it seems much 

 more owing to the disintegrated greenstone and pitchstone fragments which 

 abound. I had great difficulty in satisfying myself what this bed was, but was 

 "greatly helped by finding it again further up the burn. It is just the hard yellow 

 gravel formerly described, and the red boulder-clay which (Plate XXII. fig. 12), 

 along the burn, intervenes between it and the yellow gravelly clay, must be just a 

 tongue of the boulder-clay, lying in a depression of the surface of the yellow clay. 



For some way up the burn, the felstone rock forms one side, and the boulder- 

 clay the other of the water-course ; and no doubt, the yellow gravelly clay lies 

 hidden under the debris between, for it reappears a little higher up on the opposite 

 {i.e. the east) side of the burn, and there it distinctly underlies the boulder-clay. 

 It is intensely hard, and all the stones in it are angular. From the point where 

 it reappears, it can be followed more or less continuously for a long way, some- 

 times on one sometimes on the other side of the burn, but never, I think, occupy- 

 ing both sides at once, so that it seems to be thin. At one place, on the east side 

 of the burn, it actually seems to underlie a considerable mass of the red and 

 yellow soft shale rock which unexpectedly makes its appearance amidst the 

 felstone. At the north-west corner of the mass where alone I could get a good 

 view of their relations, the edges of the shale strata distinctly lay upon and pro- 

 jected over the yellow gravel beds. On the whole, the shale rock seemed either a 

 mass projecting amidst the felstone, and into the foundations of which the yellow 

 gravelly clay had been violently forced, or more probably a loose mass of the 

 strata which has either slipped or been pushed over the top of this yellow clay- 

 bed, yet without being upset or indeed very violently disturbed. Higher up 

 again, the yellow gravelly clay is seen directly overlaid by the red boulder-clay. 



Just above this, at 280 feet above the sea, the clay banks are 100 feet high. 

 From this point, a great shallow circular basin opens up on the hill face, and all 

 around its margin, the boulder-clay banks go sloping down into it.* 



* Just where the burn escapes from this basin, the section of the strata shown in twenty yards 

 of the burn-course is most curious. Descending the burn, one first reaches the junction of the fel- 

 stone porphyry and the underlying sandstone. The felstone porphyry crosses the burn to the 

 N.N.W., and unconformably overlies the sandstone from which it is parted by a greenstone dyke. 

 The sandstone is consideraldy hardened. A little lower down the burn the sandstone laps up on 



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