J. V. Elsden—Igneous Rocks of Lleyn, N. Wales. 308 
Elephas antiquus, Rhinoceros hemitechus, Rhinoceros tichorhinus, Hip- 
popotamus major, Bos sp., Cervus sp., and others, and states that Dr. 
Falconer and Professor (now Sir Andrew) Ramsay together dis- 
covered fragments of Cockles and other marine shells in the clay, 
and amongst gravel and stones, with which the cave is filled.' Sir 
Andrew Ramsay himself refers? to this discovery, and states that 
the Cefn caves ‘“‘ were below the sea during part of the Glacial 
Epoch, for the Boulder-clay beds reach a higher level, and with Dr. 
Falconer I found fragments of marine shells in the cave overlying 
the detritus that held the bones of elephants and other mammalia.” 
No reference is made by Dr. Buckland, in the “ Reliquize Diluviane,” 
to the Cefn Cave, but he quotes Pennant as to the discovery of two 
molar teeth and tusk of Mammoth at Halkin Mine at the mouth 
of the Vale of Clwyd, which was probably the Talargoch Mine, of 
which Dr. Buckland gives the following section :— 
Yds. Ft 
Weretable;monldyyiecpecccnenst--c0sssers- 0 2 
Clay Ne ccs tae 26 0 
Mand ands Gravel acess cssemcesesssscsseccene 68 0 
He states that pebbles of lead and some pebbles of copper occurred 
in the gravel, and that horns, teeth, and bones of Mammals occurred 
at from 40 to 70 yards from the surface, and also in the bottom bed 
resting on the subjacent rock. 
Mr. Mackintosh* found the “sand with minute fragments of sea 
shells, still adhering to. one side, of a rising branch” of the cavern 
“ascended by steps.” On the 22nd of May last Mr. Bouverie 
Luxmoore, F.G.S., and the writer, found this bed still visible, 
fragments of Tellina Balthica being determinable. 
From these observations it is obvious that the bones discovered 
belonged to Mammals, who lived before the filling up of the Vale of 
Clwyd, and the sealing of its cavern by Glacial Drift. 
V.—Norres on THE JGNEOUS Rocks or THE Luryn Promontory. 
By J. Vincenr Exspen, B.Sc. (Lond.), F.C.S. 
jee of the rocks of this district have been already described 
by the late Mr. Hi. B. Tawney, in a series of papers entitled 
* Woodwardian Laboratory Notes,” contributed to the GronogicaL 
MacazineE a few years ago. The following additional remarks are 
to a certain extent supplemental to the above-mentioned papers, and 
are founded on a microscopical examination of a large series of rocks, 
collected some few years ago during a brief visit to the Lleyn 
district. 
Commencing at the extreme end of the promontory, we find around 
Aberdaron three or four masses of intrusive rock, which are described 
in Mr. Tawney’s paper as diabase, containing plagioclase often full 
of greenish microlites, augites in small quantity, of corroded outline 
and much altered into viridite, and a large quantity of black iron- 
1 Dr. Murchison states Dr. Falconer’s visit was in August, 1859. 
2 Physical Geology and Geography of Great Britain, p. 462, 5th edition, 
3 Q.J.G.S., 1876. 
