238 Correspondence — Rev. 0. Fisher. 



consist of granite which presents signs of an E. and W. dip. A pro- 

 bability was shown that this granite is part of the mass overlying Sark. 



Finally, the age of these rocks was shown to be Archaean, and 

 attention was called to the evidence they give that some at least of the 

 Archaean rocks did not originate out of igneous masses by crush, but 

 were formed by some process which, if not aqueous sedimentation, at 

 all events was some kind of successive deposition. 



3. " Quartzite Boulders and Grooves in the Roger Mine at Dukin- 

 field." By James Eadcliffe, Esq., E.G.S. 



Quartzite boulders have from time to time been found imbedded in 

 the roof of the Roger Mine coal-seam. Similar boulders had previously 

 been described from coal-seams both in Leicestershire and the Eorest of 

 Dean. The composition of the Roger-Mine boulders was shown by 

 notes furnished by Prof. Bonney to be quartzose grit and quartzite, 

 containing some grains of felspar, epidote, and tourmaline and flakes of 

 mica. This composition resembled that of some of the pebbles in the 

 Bunter conglomerate of the Midland counties, and also that of some of 

 the Loch Maree quartzites. The boulders varied in weight from 166 

 pounds to 4 pounds, and appeared to have been dropped into the coal, 

 one boulder having been found standing edgeways. They were half 

 imbedded in the seam, half inclosed in the overlying grey shale. 



In the upper surface of the coal in the same mine, grooves were 

 found running about S. 50° E., the mean direction of faults, slips, etc., 

 being S. 26" W. The sides of these grooves were raised, as if by 

 pressure, and each depression commenced as a small groove, then 

 increased in. depth and breadth, and finally died out. 



cos/E-iEsiPOiNrnDZBisrGZE]. 



INTERGLACIAL LAND AND MAN. 



Sir, — As an item of evidence in favour of the existence of an 

 interglacial land surface, so ably maintained hy Mr. Jukes-Browne 

 in this Magazine for March, and of the presence of Man in this 

 country at the time, I send an extract out of a letter (Sept. 30, 1861) 

 from the late Dr. Bowerbank to the late Dr. Bree, of Colchester, 

 which has not, I think, been published. The occasion of its being 

 written was that Dr. Bree had shown him the cut deer's horn from 

 Clacton, described by me in the " Geologist," Aug. 1861, and figured 

 in plate ix. "I have in my possession remains of a human skull, 

 that was found mixed with bones of extinct animals at the bottom 

 of a deep dyke on an. axis of elevation, covered by the detritus of 

 the Magnesian Limestone to about one-third of the height of the 

 great crack, and the remainder then covered by the Red Drift of 

 Yorkshire ; so that it is fair to infer that it was deposited in the 

 crack, or dyke, before the submergence of that country beneath the 

 sea, and again elevated after being covered by the great northern. 

 Drift. This would appear to give an immense period to the existence 

 of Man. The finding of these bones are [sic) so well authenticated, 

 that there can be no reasonable doubt of their being in every 



