1870. | HARKNESS—WASTDALE-CRAG BLOCKS. 517 
Discussion. 
Dr. Mayn called attention to some specimens which he had 
brought in illustration of Dr. Sutherland’s paper, showing the gra- 
dual transition from a state closely resembling that of an igneous 
rock, into that of a truly stratified deposit. 
Mr. T. M‘K. Hueuzs, while admitting a recurrence of glacial 
periods, disputed the evidence in the cases hitherto brought forward. 
He adduced instances of similar accumulation of similar fragments 
in recent and ancient deposits which could not be referred to glacial 
origin; and showed how striation of the included fragments was 
frequently produced by movements in the mass subsequent to con- 
solidation, pointing out that the supposed glacial deposits of Old 
Red age were formed under conditions similar to those under which 
such irregular accumulations were formed at the present day ; that 
all the striated fragments occurred close to faults; that the Permian 
in the north of England, where it was deposited between high 
mountains, and might therefore be expected to be supplied in part 
by glaciers, contained no fragments from the higher ground of the 
Pennine range. He urged that the Natal deposit was not like a 
Boulder-clay, being ripple-marked and distinctly bedded, and that 
it had been subjected to pressure so great as to have produced di- 
stinct cleavage. 
Prof. Ramsay combated the views of Mr. Hughes, and maintained 
that there was no necessity for supposing that all the pre-Carboni- 
ferous rocks were above water at the time of the deposit of the 
Permian beds of the north of England. Still he had never main- 
tained that any of those deposits were due to glacial action, but 
only more southern beds. He pointed out that in the Natal beds 
under discussion enormous blocks of rock occurred, which were 60 
or 80 miles from their original home, and still remained angular ; 
and there was a difficulty in accounting for the phenomena on any 
other hypothesis than that suggested. He still maintained the 
probability of the occurrence of glacial episodes, not only in Per- 
mian but in other ages, as he had done now fifteen years ago. A 
Boulder-clay might be recognized, not only by the strie on the 
stones, which were not always present, but by their shape and 
the general character of the agglomeration of the beds. 
3. On the Distribution of Wasrpare-Crac Brocxs, “ Saap-FEin 
Granite Boupers,” in WexsrmorrLanp. By Professor Roperr 
Harkness, F.R.S., F.G.S. 
[Prats XXXV.] 
THE dispersion of blocks of porphyritic granite, which have been 
originally derived from Wastdale Crag, a hill lying three miles 
south of Shap, in Westmoreland, has long excited the attention of 
geologists. These granite blocks, to which the term ‘“ Shap- 
granite’? houlders has been applied, are alluded to as early as 1836 
