170 Reviews — Geological Survey Memoirs. 



Carboniferous Limestone of Derlbysliire (never previously attempted) , 

 by Mr. E. Etheridge, the Palaeontologist to the Survey, zoologically 

 arranged. From this we learn that there are of Coelenterata, 54 sp. ; 

 Echinodermata, 27 sp. ; Crustacea, 15 sp. ; Brachiopoda, 96 sp. ; 

 Lamellibranchiata, 50 sp. ; Gasteropoda, 55 sp. ; Cephalopoda, 31 

 sp. ; besides some 12 species of fishes. These remains embrace 

 about 12 localities. 



Besides three copper-plate engravings, the Memoir is illustrated 

 by 40 woodcuts of the more important sections noticed in the text. 



II. This Memoir commences, like the foregoing, with an account of 

 the researches of previous authors who have written upon these 

 formations, and describes the advances made by the officers of the 

 Geological Survey, since they commenced their investigation, now 

 fifteen years ago. 



Mr. Hull offers a classification, which is adopted by the Survey, 

 dividing the Bunter Sandstone, or base of the Triassic series, into 

 three parts, namely — 



3. Upper Mottled Sandstone. 



2. Pebble Beds. 



1. Lower Mottled Sandstone. 



Overlying these, the Muschelkalk being wanting, occur the lower 

 Keuper Sandstone, the new Ked Marl, and Eheetic Beds. The 

 greater portion of the Memoir (from pp. 29-105) is devoted to a de- 

 tailed description of this group, including its physical geology. 



The Permian rocks beneath occupy 20 pages more. There is a 

 remarkable lithological difference between the Permians of this 

 district and those of the north-eastern portion of England. The 

 general absence of Limestones from this area, and their comparative 

 abundance in the typical north-eastern area about Durham, indicating 

 a marked difference in the sources whence the materials of these 

 sedimentary strata were derived. The author recognises in the area 

 described two distinct types, the Salopian and the Lancastrian, 

 showing distinct lithological characters. 



As bearing upon the economics of the district, the author traces 

 out the original extent of the Coal strata beneath the formations 

 above noticed in central England, and attempts to determine the 

 Knes and districts of disturbance and denudation to which the Coal- 

 measures have been subjected at the close of the Carboniferous 

 period, as well as the upheaval and denudation after the Permian 

 period; and, lastly, the mode of distribution of the Permian and 

 Triassic rocks. 



The Sandstones of the lower Keuper series are the most economic 

 of all the lYiassic rocks for building purposes, and a list of the best 

 quarries is given. 



The Bunter Sandstone, as a source of water supply is also dealt 

 with, and Mr. Hull shows it to be one of the most important water- 

 bearing formations in England. 



A list of fossils is appended to the Memoir, which is illustrated by 

 numerous woodcuts. 



