528 MR. T. C. CANTRILL ON SPIRORBIS-LIMESTONE, ETC., [Aug. 1 895, 



39. On the Occurrence of Spirorbis-limestone and thin Coals in 

 the so-called Permian Rocks of Wyre Forest; with Conside- 

 rations as to the Systematic Position of the 'Permians' of 

 Salopian Type. By T. Crosbee Cantrill, Esq., B.Sc. Loud. 

 (Communicated by "Walcot Gibson, Esq., F.G.S. Bead June 

 19th, 1895.) 



Contents. 



Page 

 I. Introduction 528 



II. The South Staffordshire ' Permian ' 529 



(1) The Clent District. 



(2) The West Bromwich District. 



(3) The Wordesley District. 



III. The Wyre Forest (=EnnUe) ' Permian' 533 



(1) The Spirorbis-limestone. 



(2) General Description of the Limestone. 



(3) Course of the Outcrop. 



(4) Thin Coals in the ' Permian ' of Wyre Forest. 



(5) Fossils of the Wyre Forest ' Permian.' 



IV. Classification of the Wyre Forest ' Permian ' 541 



(1) Stratigraphical Relations. 



(2) Lithological Characters. 



(3) Analogies from other Districts. 



V, Conclusions 547 



I. Introduction. 



The occurrence of a band of Spirorbis-limestone associated with a 

 thin coal-seam in red rocks which have hitherto been regarded as 

 Permian in the district of Wyre Forest and Enville cannot but 

 affect our ideas as to the systematic relationships of these beds, and 

 may also have some influence on the mining prospects of that virgin 

 strip of red ground which, narrowing from 14 miles broad at 

 Madeley and Wolverhampton to 6 between Compton and Stour- 

 bridge, separates the coalfields of Coalbrookdale and Wyre Forest 

 on the west from that of South Staffordshire on the east. 



This red ground consists of the ' Permian ' rocks and all the 

 members of the Trias. Crossing from west to east we pass suc- 

 cessively from Coal Measures at Madeley on to ' Permian ' [e 1 of 

 the Geological Survey map], Lower, Middle, and Upper Bunter, 

 Xeuper Sandstone, and Marl, till we reach Codsall, when we again 

 pass over the same series in inverse order — omitting the Lower 

 Bunter — till we reach the Coal District of Wolverhampton. 



At the base of the Trias in this district there seems to be a 

 marked unconformity, for at Bridgenorth the base of the Lower 

 Bunter [f 1 ] is represented on the Geological Survey map, 61 S.E., 

 as approaching the base of the Permian, whereas between Enville 

 and Claverley it rests on the highest beds of the Permian ; and 



