Vol. 51.] IN THE ' PERMIAN ' ROCKS OF WYRE FOREST. 543 



Rocks from the underlying grey, yellow, and olive-coloured series 

 below. 



The red colour of some Upper Coal Measures has been referred in 

 several cases to a soaking downwards of colouring-material from 

 beds subsequently deposited, and not to a deposition of colouring- 

 matter carried on contemporaneously with the deposition of the 

 sediment. How far true this may be in other districts I am unable 

 to say. In the Wyre Forest district there are, I think, several facts 

 which go against such an idea : — 



(a) The base of the red rocks appears to be a definite horizon, and 

 seems to have been so regarded by the Geological Survey. If this 

 staining had percolated downwards, why does it apparently stop on 

 reaching one definite horizon '? It might be expected to cut across 

 the bedding and go deeper in some localities than in others. 



(b) We might perhaps expect to find occasional masses left un- 

 stained, and the intensity of staining might be expected to bear 

 some relation to the fineness or coarseness of texture of the 

 material ; but it is not proved that such is the case. 



(c) Green decolouration-spots commonly occur in the fine-grained 

 sandstones, shales, and marls of these red rocks. These are 

 supposed to be due to the deoxidizing effects of carbonaceous matter 

 embedded in the sediment during its deposition, and which, whilst 

 slowly decomposing, has reacted on the surrounding matter and 

 bleached it. It is probable, therefore, that the colouring-matter was 

 present during the bleaching, and consequently before the carbon- 

 aceous matter was destroyed. This destruction would probably 

 commence as soon as the fragment was embedded ; hence the colouring- 

 matter of such rocks must be regarded as original and not as secondary. 

 Ab least, it is difficult to imagine any process of subsequent staining 

 which could succeed in leaving small unstained spherical masses, 

 usually less than an inch in diameter, apparently differing in no respect 

 of texture from the surrounding mass. 



However this may be, it is not essential to our purpose, as many 

 beds of the Keuper Marls and Sandstones contain green spots 

 similar to those in the red rocks immediately overlying the Coal 

 Measures ; and it has never been suggested, I think, that the 

 staining of the Keuper Marls and Sandstones is a secondary effect, 

 inasmuch as there is no higher red series from which their colour 

 could have been derived. 



It seems then that, whatever the true age of these red rocks, 

 we must consider their colouring as contemporaneous, and not as 

 derived from any higher formation. 



Since writing the above, I find that the Eev. A. Irving has 

 adduced other arguments in support of the ' contemporaneous 

 colouring' theory 1 . 



It may here be remarked that the occurrence of a Spirorbis- 



1 Geol. Mag. 1882, p. 274. 

 Q. J. G. S. No. 203. 2 p 



