1870.] Geology. 115 



read before the Geological Society, in which he entered fully upon 

 this question. 



The unconformity is noticed between the Triassic and Permian 

 series, which was pointed out by Professor Sedgwick more than 

 forty years ago; the newer beds rest indiscriminately on any of 

 the older formations, whether Silurian, Devonian, Carboniferous, 

 or Permian. 



The lithological peculiarities of the beds exhibited in different 

 localities and their organic remains are noticed. Though it is as 

 well to mention that the subdivision of the Bunter Sandstone, or 

 Lower Trias, into three members, which was propounded by 

 Mr. Hull in the course of his detailed examination of the rocks 

 over a large area, was altogether dependent on inorganic evidence. 



Some little space is of course devoted to the beds of Eock-salt 

 interstratified with the Eed Marls and clays of the Keuper. The 

 Khaetic, or Penarth Beds, are also briefly noticed ; but these beds 

 have not yet been traced farther northward than the outlier of 

 Copt Heath, near Birmingham, and at Abbots Bromley, in 

 Staffordshire. Mr. Hull is inclined to regard these beds as refer- 

 able to the Triassic formation, although it seems to us better to 

 regard them as passage-beds between the Lias and Trias — the lowe£ 

 beds passing into the latter, the upper being more closely related, 

 and sometimes appearing to graduate into the Lower Lias above. 



The Physical Geology of the Permian and Triassic periods are 

 treated of ; also the distribution of the Coal Measures beneath them. 



The Bunter Sandstone is considered as a source of water-supply, 

 and is regarded, with the exception perhaps of the Chalk and 

 Lower Greensand, as by far the most important water-bearing 

 formation in England. 



In an appendix is given a list of the Fossils in the "Warwick 

 Museum, from the Keuper and Permian Sandstones, by the Kev. P. 

 B. Brodie, revised by Mr. Etheridge, Palaeontologist to the Survey. 



The second Memoir is on the 'Geology of the Carboniferous 

 Limestone, Yoredale Kocks, and Millstone Grit of North Derby- 

 shire, and the adjoining parts of Yorkshire,' by A. H. Green, M.A., 

 F.G.S., Dr. C. Le Neve Foster, B.A., F.G.S., and J. E. Dakyns, 

 M.A. They give a detailed description of the geological structure 

 of the district, together with observations on the physical features 

 and drainage, followed by an appendix, giving a list of the Carbon- 

 iferous Limestone fossils of Derbyshire, furnished by Mr. Etheridge. 



The formations described in this Memoir are as follow : — 



Kecent Alluvium and Kiver Gravels. 



Post Pliocene . . Boulder Beds. 



(Lower Coal Measures, or " Ganister Beds." 

 Millstone Grit. 

 Yoredale Kocks. 

 Carboniferous, or Mountain Limestone. 



i 2 



