Prof. J. F. Blake —Shell-beds of Moel Tryfaen. 267 
borne in Rhizodus. There are two vomers placed behind the pre- 
maxille, each of which, as in the Osteolepide, bears a large laniary 
tusk. As in the Holuptychiide, Rhizodontide, and Osteolepide 
in general, the maxilla proper bears only very small teeth. 
VII.—Tue Sueti-Beps or Morn Tryrazn. 
By Prof. J. F. Buaxs, M.A., F.G.S. 
F\HE idea that the well-known shell-bearing sands of Moel Tryfaen 
indicate a submergence to the depth at which they are found, 
cannot perhaps be yet said to be, in the language of Mr. Dugald 
Bell, ‘‘a day-dream of the past,” though it is fast becoming so. 
Towards this result there must be two stages—disbelief in the sub- 
mergence, and belief in something else. As to the first, Sir A. 
Ramsay wrote—“ He must be a bold man who could see the shell- 
beds at Moel Tryfaen and deny that the sea had been there.” I 
remember quoting this to my much lamented friend Prof. Carvill 
Lewis and receiving for reply, ‘‘one has to be bold sometimes if one 
would come at the truth.’ For my own part the result of seeing 
them for the first time would be expressed in Sir A. Ramsay’s words 
with one alteration only—the substitution of “affirm” for “deny,” 
so that with me the first step was soon taken. The second step is 
somewhat more difficult if we want. to get a clear idea of the method 
of the transport of the shells, and being recently at the spot, on 
other business, I thought it might be well to note some of the 
details which must guide us to a right explanation, but which do 
not appear to have been as yet very particularly noted. 
In the first place the supposed difficulty of getting the ‘Irish Sea 
glacier”’ to so great a height is not one which would have troubled 
Sir A. Ramsay, nor any one else who knew the district ; it is a mere 
question of a couple of hundred feet, for if ever there was a glacial 
moraine where no ice is now, it is on the west side of Moel Tryfaen. 
Indeed there are several. Coming up from the level of the Gwyrfai 
River, we pass over three well-marked long mounds, the highest, 
one having the steepest slope and looking from the lower ground 
like a long range of hills. These all run parallel from about N.NE. 
to S.SW. and they are all composed of the most typical moraine 
stuff and crowded with huge stones of which many are granite 
absolutely unknown in Wales, and other rocks which must have 
come across the sea, with occasional masses of Carboniferous rocks, 
limestone, and sandstone, only derivable from Penmon, a thousand 
feet below their present level. That such mounds as these could be 
the droppings of icebergs never did and never could enter the head 
of Sir A. Ramsay, who recognized them as certain proofs of a huge 
glacier or ice-sheet that had crossed the Irish Sea and of which they 
were the terminal (or perhaps the lateral) moraines. Now the summit 
of the highest of these long ridges is 1100 feet above sea-level. If 
the glacier could rise as high as this, it would be a small matter to 
rise a little more. It was only the presence of the sea shells which 
led to the belief that after the glacier had disappeared, the land had 
