Vol. 62.] 



CARBONIFEKOTJS ROCKS AT RUSH. 



To the north, at Skerries and at Shenick's Island, Llandovery Beds 

 with a small patch of Old Red Sandstone are also found ; conse- 

 quently, the general structure of the Carboniferous rocks between 

 liush and Skerries, although complicated by much folding and by 

 some faulting, must be that of a syncline. 



There is a general upward succession of the beds exposed near 

 Rush, as they are traced from south to north ; and the sequence, in 

 descending order, is as follows : — 



Stratigrapiiical Zones. 



Cyathaxoxia- Limestones, sometimes 

 Beds. cherty, containing chert- 



seams, interstratified 

 with shale, and decom- 

 posed locally into de- 

 calcified beds. 



[Gap, probably occupied in part by the 

 horizon of the limestone of Curkeen Hill, 

 mentioned on p. 294. 



Kate-Eocks Thickly-bedded limestone, 

 Limestones. underlain and overlain 

 by thin calcareous dark 

 j shales and thin lime- 

 : stones. Some chert- 

 seams. 



Thickness 

 in 



[Gap] 



Carl van 



Limestones. 



Thickly- and thinly- 

 bedded dark-grey lime- 

 stones, occasionally 

 pebbly, with calcareous 

 flaggy beds. 



[Gap 



Sui'RA- 



Conglomerate 

 Limestones. 



Rush 



Conglomerate 



Group. 



Passage-Beds. 



Rush Slates. 



Flaggy limestones some , 

 times pebbly, with 

 partings of black shale. 



Conglomerates, some- 

 times very coarse, 

 usually having a lime- 

 stone-matrix and inter- 

 stratified with shales and 

 calcareous sandy flags. 

 ! Calcareous sanely and 

 shaly beds. 



Black slates, often cal- 

 careous and nodular, 

 with occasional lime- 

 stone-bands & lenticles. 



200 



90 



180 



?100 



100 



500 



40 



1380 



Pal.eontological Zones. 



) 



I Upper Dibuxophyllum- 

 y Zone (Cyathaxonia- 

 Subzone). 



) 



Upper Dibunophyllum- 



ZoNE. ] 



y (r Upper) Seminula-Zos^. 



}>(? Lower) Seminula-Zoktz. 



Gap ] 



Feet. 

 70 Lower Semixvla-Zwe. 



30 



( 330 . 



I 



\ 



j 



t 170 

 40 



f 300 . 



I 1080 



Upper Stringo- 



THYRIS & LoWEU 



Semixula-Zohe. 



The Main 

 Syrixgothyris- 



ZONE. 



Upper Zaphrextis- 



Zone. 



(Base not seen.) 

 The rocks will now be described in ascending; order. 



