396 MR. G. H. MORTON ON THE CARBONIFEROUS [Aug. 1 898, 



when the cliff-side was first worked no dolomite was observed, but 



that it was penetrated afterwards. On excavating 12 feet through 



the dolomite, the bed was found to change at a joint into ordinary 



limestone ; while beneath, the rock is darker than anywhere else 



in the quarry, as shown in the section (fig. 3, p. 395). 



The following analysis of the white limestone in the quarry 



shows how small is the amount of magnesium carbonate that it 



contains : — _, 



rer cent. 



Carbonate of Hme 9892 



Carbonate of magnesia 0*o8 



Oxides of iron and alumina 0'20 



Sulphate of lime trace 



Insoluble siliceous matter 050 



100-00 



Few fossils occur in the limestone, but Mr. Storey has preserved 

 most of those that were found in the quarry, and they are tabulated 

 in the list of species on pp. 392-393, which includes some of my 

 own collecting. 



The Lower Brown Limestone must occur below the floor of the 

 quarry, north of the principal fault. It is probably represented 

 along the inaccessible base of the cliffs just above the range of the 

 tides, for a bed of dolomite about 30 feet in thickness crops out on 

 the west side of Forth Dyniewyd, the little bay at the extreme 

 north of the headland, 200 yards from the quarry, where copper 

 is reported to have been found immediately above the sea-level. 



At the north-eastern corner of the Head there is a remarkable boss 

 of limestone, named Trwyn-y-Fuwch, the top of which is 100 feet 

 above the sea, and it appears to have slipped down from a cor- 

 responding recess in the cliffs about 100 feet higher. The principal 

 reason for this conclusion is that the obscure bedding in the fallen 

 mass is nearly on end, and the limestone is quite unconnected with 

 the adjacent cliffs. The fall seems to have occurred in pre-Glacial 

 times, for there is a deposit of red earth containing fragments of 

 chert, and a bed of fine-grained white sand covered with Boulder 

 Clay, 150 yards wide, between the isolated mass and the cliffs from 

 which it is supposed to have fallen. Mr. Storey came independently 

 to the same conclusion, and I am much indebted to him for the 

 facilities which he afforded me when at the quarry. 



Along the worked face of the excavations there were several 

 fissures, probably widened joints in the rock filled with red drift. 

 About 7 years ago one of these was found to contain the teeth 

 and bones of bear, hyfena, rhinoceros, and other mammalia a few 

 feet above the floor of the quarry,^ while some 30 or 40 feet higher 

 a human skull was found, and near the top of the cliff a bronze 

 spear-head 12 inches in length. All these objects had probably 

 fallen or had been washed into the fissure at different times, from 

 pre-Glacial to Recent. 



^ These were presented to the Liverpool Free Public Museum, but seem to 

 have been lost. 



