I*rof. Lapicortli — Cambrian Rocks near Birmingham. 563 



Permia^s^s of Lancashire. 

 North Lancashire. Furness Abbey and Hawcoat. 

 Upper Permians. (St. Bee's Sandstones). 

 Middle Permian. Magnesian Limestone of Stauk (Scliizodus). 

 Lower Permian. (Penritb Sandstone, absent.) 

 Lancashire Fi/lde. 



Upper Permian ? (Garstang Sandstones.) 

 South- West Lancashire. 



Upper Permian. (Absent.) 



Middle „ Magnesian Limestone, 6 feet at Skillaw Clough. 



-[■ / Marls, 30 feet. 



ijowev „ \ Sandstone, 40 feet. 

 South Lancashire. 



Middle Permian. Marls and Limestones (ScMzodus) 300 feet. 

 J rCoUyliurst Sandstones 300 feet at Manchester 



J^ower „ j thickening north-east to 1000 feet. 



Unconformity. 



It is obvious that I could not give a reference to an unpublislied, 

 paper; but my own statement was: "He (Mr. De K.) considers 

 the ' Upper Permian ' of the Survey to be wanting in South Lan- 

 cashire, and is doubtful if the Garstang Sandstones ought to be so 

 considered. Mr. De Eance also considers the so-called ' Upper 

 Permian ' of North Lancashire to occupy the same horizon as the 

 St. Bee's Sandstone." Further comment is needless. 



VIIL — On the Discovery of Cambrian Eooks in the Neigh- 

 bourhood OF Birmingham.^ 



By Chas. Lapworth, F.G.S., etc., 

 Professor of Geology and Mineralogy, Mason Science College. 



THE geology of the neighbourhood of Birmingham is one of more 

 than ordinary interest, owing to the great variety of geological 

 formations exposed within its area. Its rocky structure was investi- 

 gated about thirty years since by the officers of the Geological 

 Survey of Great Britain, and its several geological formations laid 

 down upon their maps, and described in detail in their various 

 explanatory memoirs. Some of these publications — notably the 

 maps and descriptions of the South Staffordshire Coalfield — have 

 subsequently become classic in the literature of Geology. Since 

 these publications were issued, however, the science of Geology has 

 made great advances, more accurate and detailed methods of research 

 among the older rocks have been developed, aad their application to 

 the study of the strata of the Birmingham district has recently 

 resulted in the detection of several most interesting facts which 

 escaped the notice of the earlier investigators. 



In the geological history of the Birmingham district three grand 

 historical periods have long been recognized — the deep-water period 

 of the Silurian, the Estuarine period of the Carboniferous, and the 

 Continental or inland-lake period of the Permian and Triassic. 



The oldest strata of the region have hitherto been supposed to be 

 of Upper Silurian age. They compose the rocks of the Lower 



' Reprinted from the Proceedings of the Birmingham Philosophical Society, 

 vol. iii. page 234. 



