14 



PEOCEEDINGS OF THE GEOLOGICAL SOCIETF. 



[Nov. 21, 



The fossil remains in these old hollows in Mountain-limestone at 

 the bottom of the Liassic sea are in incalculable multitudes ; and on 

 splitting blocks upon which they weather out in profusion, the frac- 

 tured surfaces give indications of as many others. Some of the 

 fossils are perfect even in their most delicate ornamentation ; others 

 are worn, having been rolled ; and myriads are in fragments. The 

 smaller fossils stud the blocks, and consist for the most part of frag- 

 ments of Madreporaria and Pentacrinites, of Cidaris spines and plates, 

 and of fragments of large and small Lamellibranchiata ; and with 

 these are mixed the shells of tiny Gasteropoda. The larger fossils 

 consist of perfect spheres of Isastrcea glohosa, DunC. (and fragments 

 of them), of blocks more or less gibbous of another Isastreea, of flat 

 or dendroid pieces of Astroccenice, and of more or less fragmentary 

 Thecosmilice and Montlivaltice ; and amidst these are more or less 

 perfect Cerithia, Turritellce, large Pleurotomarice, Straparolce, Neri- 

 tojpsides, many rugged Ostrece, and more or less perfect Limes. There 

 are also Polyzoa and Serpulce. All are mingled together, and here 

 and there are some remanie species of Syringojoora, Ampleocus, 

 Cyathojyhyllum and Lithostrotion. The profusion of perfect speci- 

 mens of many species of Madreporaria is quite characteristic of the 

 deposit. Considering that many of the fossils are found as casts, 

 that others have suffered from a destructive fossilization, and that 

 many kinds of stone enter into the composition of the deposit, it is 

 very remarkable that so many species should be determinable from 

 so many specimens. 



The most common fossils are Madreporaria ; and portions of some 

 Astrocsenian or other are found on every block. Specimens from 

 Ewenny resemble those from Brocastle ; and it is evident that the 

 beds are on the same geological horizon. 



Brocastle may be considered a typical deposit ; and in all proba- 

 bility the remarks made upon it will apply to coralliferous beds near 

 Cowbridge, which rest upon Mountain-limestone, and to a fossili- 

 ferous bed near Laleston, where vast numbers of a Thecosmilia are 

 found. But further information is required before several other 

 Liassic deposits resting upon Carboniferous limestone can be asserted 

 to be on the same horizon as Brocastle. 



The following is a list of the species of Madreporaria, from the 

 Brocastle beds, which have not been hitherto described : — 



Monthvaltia simplex, sp. nov.'^ 



Walliee, sp. no v. 



Brodiei, sp. nov. 



Murchisonise, sp. nov. 



pedunculata, sp. nov. 



brevis, sp. nov. 



Thecosmilia irregularis, sp. nov. and 

 1 var. 



■ Terquemi, sp. nov. 



■ affinis, sp. nov. 



Thecosmilia Walliae, sp. nov. 



dentata, sp. nov. 



plana, sp. nov. 



Isastrsea giobosa, sp. nov. 

 Latimiieanclra denticulata, sp. nov. 

 Cyathoceenia dendroidea, sp. nov. 



costata, sp. nov. 



Astrocffinia plana, sp. nov. 



dendroidea, sp. nov. 



minuta, sp. nov. 



* These species, having been drawn on stone and described for the PaIa;on- 

 tographical Society, will be published in its volume for 1866. 



