TRANSACTIONS OF THE SECTIONS. 71 



On the Loivest Beds of the Clifton Carhoniferous Series. 

 By W. "W. Stoddart, F.G.S., Bristol. 



The author, after briefly describing the Clifton scenery, and the advantages that 

 locality affords for geological study, gave a short summary of the rocks which range 

 in one unbroken line from the Millstone-giit on Brandon Hill to the Old Ked Sand- 

 stone below Cook's Folly. 



It is to the lowest beds of these lying immediately on the Old Red that this 

 paper referred. 



The highest of the beds now in question is the well-known palate bed, contain- 

 ing a large nimiber of the teeth and spines of fishes, Iclithyocopri, Brachiopoda, 

 Pteropoda, Polyzoa, &c. 



The principal fossils from the bed are — 



Fenestella Cladodus conicus. 



Ceriopora rhombifera. Chomatodus linearis. 



Spirifera bisulcata. Ctenacanthus tenuistriatus. 



glabra. Helodus Isevissimus. 



Discina nitida. Psammodus porosus. 



Lingula mytiloides. Coprolites. 

 Conulai'ia quadrisulcata. 



Under this are seen three beds of red crystalline limestone, the middle one of 

 which the author described in the ' Annals of Natural History,' 1857. 



It dips to the S.S.E. at an angle of 68°, and contains one of the most extraordi- 

 nary assemblages of fossils perhaps ever seen. All of them do not exceed ^^th of 

 an inch in diameter, and many are less than 100th of an inch. They are composed 

 of a peculiar combination of peroxide of iron and silica, and are perfectly insoluble 

 in cold nitric and hydrochloric acids. 



The fossils constitute more than 20 per cent, by weight of the rock. From a 

 pound weight of the limestone were obtained more than a million and a half of 

 perfect fossils besides debris. 



It was most probably a bank exposed to the littoral waves of a Carboniferous sea 

 which would wash away the large shells, leav-ing the smaller — just as we now see 

 going on at many places of our o^vn coast, as Silsea Bill, Caldy Island, &c. 



The fossils more commonly found are — 



Poteriocrinus. Ceriopora rhombifera (Goldf). 



Platycrinus Pleurotomaria pygmaea (n. sp.). 



Cythere ovalis (n. sp.). Euomphalus triangulatus (n. sp.). 



Cy therella lunata (n. sp.). Natica plicistria ( Yoimg). 



Passing downward through a thickness of 8 or 9 feet, the author found a bed of 

 dark gi'ey shaly marl. It probably corresponds to No. 428 in Mr. WiUiams's Sec- 

 tion, and is the most important of the whole series to the geologist. It contains 

 fossils that occur in no other of the limestone beds at Clifton. The principal of 

 these are 3£odiola Macadumi, Arictda Damtioniemis, Katica 2}licistria, Spirorhis otii- 

 j)luilodes, Cypridina Scotohurdigalemis, Cypriduia subrectus, Knorria dichotoma, &c. 



The Modiolce are in immense masses, and sometimes covered with the remains 

 of Entomostraca and Spu'rorhis. Below this shaly bed continue 70 feet of alter- 

 nating limestones, shales, and marls, and then 30 feet of passage beds into the Old 

 Red, which properly commences by the well-known quartzose conglomerate. 



The author then alluded to the corresponding Lower Limestone shales in the 

 northern pai-t of Derry, and the section described by General Portlock on the 

 Moyola and Altagowan rivers, and pomted out the very great similarity both litho- 

 logically and paleeontologically. 



After comparing these with the Coomhola grits of Messrs. Jukes and Salter, 

 and the Marwood Section of hitherto so-called Upper Devonian in Devonshire, the 

 author showed that no doubt could exist of the Modiola shales at Clifton being a 

 representative of them all. It is true that the larger Brachiopoda are missing at 

 Clifton that ai'e foimd in Ireland, where the thickness of the lower shales is enor- 

 mous, as at Glengariff Harbour ; but, on the other hand, in those Irish sections 



