GEOLOGY OK DERBYSHIRE 221 



on the whole of the four-fold division given before, its highest or 

 superior portion being 



2. — The Red Marls and Gypsum. 



These, where they occur in Derbyshire, differ in no respect from 

 their character in Leicestershire, except in the presence of the gravel 

 before mentioned. The section at Chellaston is 



FEET. 



Dark-brown marl with green stains and streaks, having many 

 thin bands of fibrous gypsum and lenticular masses of 

 it ; thickness varying according to the surface of the 



ground, but generally 40 



Marl, full of gypsum in intertangled veins 6 



Hard gypsum without marl 14 



The marl is indurated, and splits into small cubical lumps, as is 

 often the case with the marls of this portion of the new red sand- 

 stone. It contains no fossils, so far as I am aware, except those 

 belonging to the gravel before mentioned. The thickness of this 

 formation in Derbyshire is probably not greater than 150 feet. 

 Below it we find 



3. — The Red and White Sandstone. 



These likewise contain beds of marl in their upper portion, but of 

 comparatively insignificant thickness, and having little or no gyp- 

 sum. The sandstones vary in colour from a dark reddish-brown to 

 a clear white, and in hardness from a good compact building stone 

 to a friable sand. It has the same characters which distinguish this 

 part of the formation in Leicestershire, Warwickshire, and Worces- 

 tershire. The beds of white sandstone form a considerable portion 

 of the whole, but are variable in their thickness and extent, thinning 

 out and then setting in again. In Derbyshire, however, there are 

 nowhere any good sections exposed in this formation, owing to the 

 levelness of the country it composes. The same cause prevents us 

 giving even a guess as to the amount of its thickness in this county. 

 I was not lucky enough to discover any fossils in this formation 

 myself, but Mr. Meynell, of Tapton Grove, near Chesterfield, shew- 

 ed me a portion of a calamite and fragments of other vegetable re- 

 mains from a (juarry near Langley, which agreed exactly with those 

 found in this sandstono in Worcestershire. The appearance of the 



