26 
HAYDEN: GEOLOGY OF SPIT!. 
Coral limestone. 
Near the top of the limestone is a band containing numerous Cystidea, 
chiiif\y Pyrocystites pirum, Barr., and Craterma sp. 
This bed therefore in all probability belongs also to the lower Silu- 
rian. It is overlain by about 40 feet of hard, grey limestone and* 
greenish shale, from which no recognisable fossils have been obtained. 
The next bed (5) is a shaly limestone, containing numerous badly pre- 
served brachiopods and gastropods, with corals ; most of the brachiopods 
are too badly preserved for identification, but include Strophomena 
rhomboid alis, Wilck., Meristella [Atrypd) cylindrica, Hall, Orthis sp. 
The gastropods belong to the genus Pleurotomaria, and the corals 
to Cyathophyllum and Chxtetes : Orthoceras sp. is also common. 
This is overlain by about 50 feet of grey limestone, contain- 
ing large numbers of well-preserved corals, which 
include— 
Haly sites caten-ulatus. Linn. 
Chesiefes yak, Salt. 
Lyellta sp. 
, Favosites sp. 
Cyathophyllum sp. 
Syringopora sp. also occurs. 
Halysites catenulatus and Chaetetes yak are very common. 
This bed appears to be Mr. Griesbach's "hard, dark, concretionary 
coral limestone," which he regarded as devonian. 
The next bed (7) consists of shaly limestone and grey siliceous and 
" Red crinoid lime- A^ggy limestone, weathering bright brownish-red. 
stone." j|. contains numerous fossils, mostly, however, 
preserved only as casts and moulds : in places the weathered surface of the 
rock is covered with fragments of crinoids ; it therefore probably repre- 
sents Mr. Griesbach's " red crinoid limestone." The shaly bands contain 
numerous brachiopods, of which the following are the commonest : — 
Orthis thakil var. convexa, Salt. 
„ „ „ siib-divisa, Saft. 
„ cf. elegantula, Dalm. 
Leptcena depressa, Dalm. 
Chonetes sp. 
Orthoceras sp. also occurs. 
( 26 ) 
