542 ME. T. C. CANTRTLL ON SPIRORBIS-LIMESTONE, ETC., [Aug. 1895, 



(1) Stratigraphical Relations. 



It is to be noticed that Murchison states 1 that in many places 

 these Lower Sandstones and Marls may be seen to pass down con- 

 formably into Upper Coal Measures. On the other hand, Ramsay 

 was of opinion that there was a considerable unconformity between 

 the ' Permian ' and the Carboniferous System generally. 2 Probably 

 both observers were in part correct ; the floor on which the ' Per- 

 mian ' beds were being laid down was probably undergoing a corruga- 

 tion, both on a large and small scale. Thus, while in one part of the 

 area continuous and uninterrupted deposition took place, Upper Coal 

 Measures graduating into ' Permian,' yet in another part the 

 Upper Coal Measures and indeed still lower members of the Carbo- 

 niferous and older rocks may have been elevated into ridges, more 

 or less eroded, and then sunk beneath the red sediments. Hence 

 we cannot well argue as to the affinities between the ' Permians ' 

 and Coal Measures from this point of conformity or unconformity, 

 as in some places there appears to be conformity, and in others a 

 certain amount of break. 



So far as the Wyre Forest district is concerned, Murchison was 

 of opinion that the Upper Coal Measures and ' Permians ' are con- 

 formable to each other, and quotes a section at Chelmarsh as 

 showing the passage of one into the other. But in the neighbour- 

 hood of the Trimpley anticline there is some slight evidence of 

 unconformity. 



It is important to remember, too, that it is tolerably certain that 

 in the Coalbrookdale district there is a vastly greater break between 

 Middle Coal Measures and Upper Coal Measures 3 than between the 

 latter and the ' Permian.' In some places the Upper Coal Mea- 

 sures rest upon the highest, and in other places upon the lowest of 

 the coal-seams of the Middle series. 



(2) Lithological Characters. 



With regard to lithological characters the ' Permian ' rocks 

 possess several which separate them from the underlying Coal 

 Measures. They are, on the whole, red or reddish-purple in colour 

 — often of a bright salmon tint ; and they contain beds of calcareous 

 conglomerate (shingle-beaches of limestone and other pebbles) and 

 trappoid breccia, which do not appear to resemble anything found in 

 the underlying Coal Measures. But, of these points of difference, 

 perhaps that of colour is the most important. The general change 

 in colour is undoubtedly the strongest reason for separating the Red 



1 Proc. Geol. Soc. vol. ii. (1835), p. 117; also 'Silurian System,' 1839, 

 pp. 92, 131, 132. 



2 Quart. Journ. Geol. Soc. vol. xi. (1855) pp. 187, 204. 



3 See Marcus Scott, Quart. Journ. Geol. Soc. -vol. xvii. (1861) p. 457 ; also 

 Daniel Jones, Geol. Mag. 1871, p. 200. 



