﻿Geological Society of London. 235 



opinion, there is perfect conformitj'^ between the Mudstones and the 

 underlying Coniston Limestone. They regard the G-raptolitic Mud- 

 stones as constituting a definite geological horizon of more than 

 local importance, as they have been recognized in Ireland, Sweden, 

 Carinthia, and Bohemia. 



The Grraptolitic Mudstones are succeeded by the " Knock beds," 

 so called from their great development in Swindale Beck, near 

 Knock. Wherever they occur, they consist chiefly of pale-green, 

 fine-grained slates, very ashy in appearance, and presenting many 

 dendrites, and frequently crystals of cubic pyrites. There is no 

 evidence of unconformity between them and the underlying Mud- 

 stones. The former contain scarcely any fossils. They are directly 

 surmounted by the " Coniston Flags," representing the Denbighshire 

 Flags of North Wales, which have been shown to be of Upper 

 Silurian age. Hence the authors conclude that the Knock beds 

 must be either the basement series of the Upper, or the summit 

 series of the Lower Silurian, or else a group of passage-beds between 

 the two. The palseontological evidence is insufficient to settle the 

 point, but it tends to show that the Knock beds are at the base of 

 the Upper Silurian, an opinion which is corroboi'ated by their 

 lithological resemblance to the Tarannon slates of Wales. 



The paper concluded with' an appendix on the Irish rocks referred 

 to above. 



2. " On a new Area of Upper Cambrian Kocks in South Shrop- 

 shire, with the Description of a new Fauna," By C Callaway, Esq., 

 M.A., F.G.S. 



The purpose of the author was to prove that certain olive, mica- 

 ceous, thin-bedded shales exposed at Shineton, near Cressage, and 

 covering an area of eight miles in length by two in the greatest 

 breadth, which had been mapped as Caradoc in the survey, were of 

 Tremadoc age. They were seen clearly to underlie the Hoar Edge 

 Grit, the lowest beds in the district, with Caradoc fossils ; and no 

 rock distinctly underlying the shales could be detected. The evi- 

 dence for their age was chiefly palgeontological. With the exception 

 of Asaphus E-omfrayi, a Tremadoc form, the species are new. 

 Genera such as Oleniis, Conocoryphe, Obolella, and Lingulella, 

 suggested a very low horizon, but two Asaphoid forms (though not 

 typical AsapM) pointed in an opposite direction. Corroborative 

 evidence was found in a correlation of the shales at Shineton with 

 the I)ictyonema-&\idlQ^ at Pedwardine and Malvern. It was shown 

 from lithological characters and from fossils that the shales at the 

 three localities were of the same age ; and as the beds at Pedwar- 

 dine and Malvern were, on their own testimony, admitted to be of 

 Lingula-Qa,g or Tremadoc age, the Shineton shales were inferred to 

 be on the same horizon, the Asaphids leading the author to adopt 

 the younger of the two formations. He was of opinion that the 

 Black Shales of Malvern (Dolgelly beds) were not represented in 

 the Shineton area. He announced the discovery of the Hollybush 

 Sandstone, forming a continuous band between the Shineton Shales 

 and the Wrekin axis, recognized by the occurrence of Kutorgina 



