281 
ing in tlie Sandstone or Shales, as a colourless protoxide, has 
been changed by the addition of oxygen to a peroxide, or red 
oxide of Iron, and may have caused the red colour of the 
rocks. This theory is borne out to some extent by the fact, 
that in many instances where the rocks have been traced to 
a greater depth, the red colour has been found to disappear, 
giving place to the usual, or natural grey or yellow colour, 
and farther, by the frequent occurrence of isolated patches, 
or nodular concretions of a deep red or purple colour, whilst 
the general colour of the rock is grey. 
The object of this paper is to give a . little fuller considera- 
tion to the relation of the Red Rocks to the overlying Per- 
mian Limestone than, so far as I know, has hitherto been 
done, and to endeavour to show that the Limestones are, 
throughout their entire extent, deposited uncomformably to 
the rocks beneath them, and that where any apparent con- 
formability exists, it is merely the effect of parallelism of the 
beds of very local extent. 
(2) SHORT NOTICES OF PREVIOUS ^VRITINGS ON THE SUBJECT. 
J. Farey. — "Uncomfortable position of the Pontefract Eock of Sand- 
stone, with respect to the subjacent Coal Measures, as shown in the 
new geological map of Yorkshire ; and regarding some errors 
therein as to parts of the ranges of certain rocks, in the Coal Series." 
Ann. of Phil., Ser. 2, Vol. v., p. 270. 
Prof. Jno. Phillips. — "Geological observations made in the neighbour- 
hood of Feriy Bridge, in the years 1826-28." Phil. Mag., Ser. 2, 
Vol. ii., p. 401. 
Bev. a. Sedgwick, F.R.S., &c. — " On the Geological Relations and 
Internal Structure of the Magnesian Limestone and the Lower 
portion of the New Red Sandstone Series, in their Ranges through 
Nottinghamshire, Derbyshire, Yorkshire, and Durham, to the 
Bouthern extremity of Northumberland." Trans. Geol. Socy., 
2nd. Series., Vol. iii., pt. i., p. 37. 
Traces the western escarpments of the Permian formation throughout 
its entire length, giving a minute and elaborate descrijition of the 
physical and geological features of the country. The Red Sandstone 
