3IOOE2:; AI3^'0RMAL SECOXDART DEPOSITS. 533 



10. Langan Lead-mine, Sutton Stone, and Conglomerates. — It has 

 been stated that there are thick conglomerates interposed bet-vreen 

 the Sutton Stone and the Carboniferous Limestone. Though not 

 visible in the Sutton quarries, it has been pointed out that they are 

 present under the Sutton Stone, when the base of the cliff section is 

 examined at Iott Trater, though no evidence of their thickness can 

 thus be arrived at. Under the Sutton stone at Dunravcn they are 

 also to be recognized. The Lias at Langan is deposited in a deep 

 basin in great part sui'rounded by Carboniferous Limestone. The 

 lead-mine at this place, mentioued by Mr. TaTmey, is about a mile 

 and a half north-east of Brocastle, and considerably below the hori- 

 zon of its coralliferous conglomerates. 



" The sinking was commenced in a Liassic vein ; and as the " coimtry '* 

 had to be removed, by which the miners mean the stratified or other 

 deposits on each side of the vein, these were proved to the bottom 

 of the shaft. At the surface M'ere regularly bedded, but finely con- 

 glomeratic, dense limestones with thin intervening beds of marl. 

 Although fossils are plentiful on their weathered edges, but few could 

 be extracted. In the marls, PoUicipes rhomhoidalis, Moore, and Pen- 

 tacrinites are frequent. Following the above limestones, the Sutton 

 Stone was passed thi'ough, from which were obtained Patella Dun- 

 Iceri, Terq., and Pecten Pollucc, Taw. 



Immediately below the Sutton Stone unstratified conglomerates 

 were found, and passed through to the depth of 150 feet, and still 

 continued when the mine was abandoned. Ts'o organic remains could 

 be detected in them. All these conglomerates are therefore clearly 

 interposed between the Sutton Stone and the Carboniferous Lime- 

 stone, which no doubt forms the bottom of the basin at Langan*. 

 In the stratified beds above the Sutton Stone, there are many species 

 of Cardinia and Pentacrinus ; and I also obtained the following : — 



Ammonites angulatus. 



Lepidotus-scales. 



PoUicipes rhomboidalis, Moore. 



Entomostraca, 2 spp. 



Astarte irregularis, Tcrq. 



Ostrea arietis. 



Anoraia irregularis, Tcrq. 



Cardita tetragona, Terq. 



11. Inadmissih'dity of the term " Pnfralias.'' — For a considerable 

 time all the beds at the base of the Lower Lias, below the " "W^hite 

 Lias," including the bone-bed and the Avicida-contorta series, we^o 

 oscillating between a classification by some authors with the Keuper 

 and by others with the Liassic series. The indefinite term " Infra- 

 lias" was then introduced, and has begun to be recognized in 

 geological nomenclature. In my paper on the " Zones of the Lower 

 Lias, &c.," I pointed out the marked distinction these beds pre- 

 sented from the Keuper at their base on the one hand, and the Liassic 

 beds above, and proposed that, including the " White Lias," they 



* As these conglomerates both at Sutton and Langan follow immediately 

 below tbo Sutton Stone and graduate into it, there appears little doubt that 

 they must be assigned to the Liassic period. 



Ortbostoma arena, Tcrq. 

 Pleurotomaria lens, Terq. 

 Turbo rotundatus, Terq. 

 Trocbus Juliani, Terq. 



Langanensis, Moore. 



Trochotoma cly[)eus, Terq. 

 Asti'occenia gihhosSi.Martin. 

 Tliecosmilia Michelini, Tcrq. 



