1862.] BOLTON ULVEKSTON. 277 



plant-bearing deposit, when cut through by the gallery, had thickened 

 to fifteen feet. The wood imbedded in the lower seams of the clay 

 was partly converted into a soft, blue pigment, having phosphate of 

 iron for its colouring-matter. 



_ Thus it appears evident that the areas anciently covered by the 

 lake -water were those of the long valleys which course sinuously 

 between the low hills of Purness. 



A second adit, driven southward from the bottom of the shaft, cut 

 into a good bed of iron-ore at twenty feet from the commencement. 



Glancing backwards for a moment at this scant record of a local 

 and comparatively insignificant deposit, I diffidently claim a value 

 for it in any scheme cast for the determination of Pleistocene time. 

 In the absence of great and sudden cataclysmal irruptions of water 

 which could fill valleys with drifted material, and of which I conceive 

 we have no settled evidence, it appears to me that the time required 

 for the deposition of this great thickness of nearly 100 feet of 

 transported material upon the comparatively flat surface of this 

 lacustrine clay by the ordinary degradation of the low hills around 

 it must be one far extended beyond our ordinary notions. The 

 material of which the whole thickness of the superimposed deposit 

 is composed is of strictly local origin, and, in the absence of violent 

 sweeps of north-lying water, and sudden fillings-up, by such means, 

 of the shallow valleys by the locally derived detritus, I am at a loss 

 to see how the distribution could have been effected, except by 

 ordinary aqueous and pluvial agencies extended through a long 

 period of time. 



P.S. — Since the above paper was communicated, the miners have 

 exhausted the iron-ore in the pit, section fig. 2 ; and then they sank 

 to a further depth of about 30 feet, but without getting through 

 the soft limestone. They have now left it altogether, and have sunk 

 another shaft about 220 yards to the north of it ; and at about the 

 same relative depth they have found the same deposit, containing 

 vegetable remains, (fee, but not in abundance. The miners say also 

 that they found the same material in a shaft about 200 yards north 

 from this new shaft, that is, about 420 yards north of No. 2 section. 

 If this be correct (and I have no reason to doubt it), it demonstrates 

 that the deposit covers a triangular area, the three sides of which 

 are respectively 420, 450, and 600 yards in length.— May 24, 1862, 

 .T.B. 



