﻿Vol. 64.] 



CARBO:^flFEKOUS ROCKS AT LOTJGHSHINNr. 



429 



J ^is 



00 s 



'II 



h4 



~2 (o 







1^ 



CO 



CO 



N 



<u o \ 

 C/) " 



t 



I -2 



i^ o 

 a> o 



ifi 



o 

 U 



C 

 rt 



:3 



Hill Limestone.^ From the beds of this 

 group Dibunojphylluni, Clisiopliyllum, 

 Lithostrotion irregidare, and ' Petalaxis ' 

 have been obtained : hence it is clear that 

 the beds lie somewhere in the Dihuno- 

 pJiyllmn-Zone. The upward development 

 of this interesting conglomeratic episode 

 is unfortunately interrupted by the fault 

 that brings in the Lane and Holmpatrick 

 beds. 



(D) The Lane Congloiiierate_, with 

 its Under- and Overlying Limestones. 



The remainder of the coast-section is 

 of quite simple geological structure, the 

 beds dipping with gentle undulations at 

 low angles to the north-east and north. 

 They are separated from the Dihuno- 

 ^^Jiyllum-Beds just described by an angular 

 fault, the importance of which will be 

 discussed presently. 



The sequence of the beds north of the 

 fault is as follows, in descending order 

 (see fig. 13) : — 



(c) Holmpatrick Limestone. Light-grey 

 limestone, dolomitized in parts. Top 

 not seen. About 180 feet exposed. 



(h) Lane Conglomerate. Very coarse con- 

 glomerate. 200 feet thick. 



(a) Lane Limestones. Limestones, fre- 

 quently pebbly. Base not exposed. 

 About 60 feet seen. 



The beds are named from the town- 

 lands in which the exposures occur. 



The Lane Limestones, for the most 

 part evenly-bedded but sometimes tending 

 to a lenticular arrangement, dip sea- 

 wards at an angle of about 15° and pass 

 up into the Lane Conglomerate. Some 

 of the limestones contain an abundance 

 of tiny white quartz-pebbles, while others 

 are filled with round lumps of limestone 

 which appear to be of detrital rather 

 than of concretionary origin. Small 

 Zaphrentid and Densiphyllid corals are 

 abundant in these beds, also Choneies cf. 

 comoides, Eaomphalus^ etc. 



The Lane Conglomerate is a very 



Quart. Journ. Geol. Soc. vol. Ixii (190G) pp. 299 & ;J04. 



