378 Correspondence — Miss C. A. Raisin. 



of the southern quarry, gains support from the work detailed in this 

 paper, although the results of recent excavations show that a rock 

 of different lithological character from that of the northern quarry- 

 probably underlies the rocks of the southern quarry. 



A list of the fossils found in the lowest beds of the southern 

 quarry includes eleven species not yet found in the " Oolite " of the 

 northern quarry ; a second list comprises the fossils found just below 

 the " Rag " in the Oolite of the southern quan-y. Both these faunas 

 are intermediate between those of the "Eag" of the southern and the 

 " Oolite " of the northern quarry. 



During the deepening of a well less than a quarter-mile north of 

 the northern quarry, fossils identical with those of the northern 

 quarry were found ; the lowest rock enclosed lumps and streaks 

 of bluish-black clay, as though the Oxford Clay were not far 

 underneath. From this excavation and other evidence, the author 

 considers that the "Oolite" can hardly be less than 40 feet thick, 

 and that this rock is geologically below the " Eag " of the southern 

 quarry. 



Excavations at the southern end of the ridge and south of the 

 southern quarry show that beds containing the "Eag" fauna are 

 conformably underlain by a rock 16 feet thick, identical with the 

 "Elsworth Eock" both in lithology and fossils. The discussion of 

 the fossils from this rock and that of Elsworth itself indicates that 

 " thei'e is no longer any palaeontological evidence for correlating it 

 with the Lower Calcareous Grit rather than with higher beds." 



On the whole, the author is in favour of the view that the 

 " Oolite " of the northern quarry is the lateral equivalent of the 

 Elsworth Eock seen in the excavations south of the southern quarry. 



The next meeting of the Society will be held on Wednesday, 

 November 9, 1898, 



coI^I^E!s:po2^^3DEl^^G:E]. 



"THE LLANBERIS UNCONFOEMITY." 

 Sir, — The letter from the Eev. J. F. Blake which appears in 

 your issue of July, p. 335, seems to call for a short comment 

 from me. The paper by Professor Bonney and myself published in 

 the Q.J.G.S. for 1894 was founded on the work done in Wales by 

 both authors. Previous to my investigations, the work of Professor 

 Bonney had led him to conclusions mainly identical, I believe, with 

 those which we enunciated. He had visited the district after the 

 publication of his earlier paper ; ^ and he re-examined in 1893 the 

 critical sections in both the Bangor and the Llanberis area. His 

 opinion on the question of the ' unconformity ' which has been claimed 

 as exhibited along the L. Padarn railway, was drawn from his own 

 examination of the section. Of the sections not examined by him, 

 the only important one, I believe, is that at Bryn Efail, and of those 

 rocks he saw all my specimens. But his scrupulous sense of justice 



^ I believe tliis was iu 1880 ; I am not sure of the exact year. 



