24 
cumstances permian and triassic strata have been often 
supposed to indicate tlie presence of coal under them. No 
doubt they do where profitable seams of coal disappear 
under them, but when millstone grit or mountain limestone 
in Lancashire and Cheshire disappear on their dip under 
permian or triassic strata, such strata do not give any evi- 
dence of the existence of profitable coal seams under them, 
but only of beds of mountain limestone or millstone grit 
seen near them. This holds good only for the southern or 
midland districts of England, so far as profitable coal is con- 
cerned, for it is well known that in Scotland both these 
deposits contain valuable seams of coal. 
Mr. Hull in his map of the district lays down the country 
from Macclesfield to Stockport so far as it relates to the coal 
measures, by supposing the latter strata on their dip as being 
bounded by what he terms the “ red rock fault,” whereas I 
have in all my papers described the coal measures in that 
district as only overlaid by permian or triassic strata, there 
being in my opinion no evidence of “ a fissure along which 
relative displacement of the adjoining rock masses has taken 
place”; such not having been given, it can only be put for- 
ward as hypothetical and without any evidence of facts to 
sanction it. When my papers were published there was 
plenty of evidence in support of my views in other districts, 
but not so much near Stockport. However, this has lately 
been supplied on the line of the so-called Red Rock Fault, 
in a shaft and. bore hole at Brinnington, where, under a. soft 
red sandstone without pebbles, most probably trias (lower 
soft red), the coal measures containing seams of coal were 
met with, thus clearly showing that such strata there 
were not dislocated by a fault, but simply overlaid by trias. 
In works of such authority as the geological maps and 
memoirs of the Survey, every care should be taken to ascer- 
tain the boundaries of the workable coal fields in a manu- 
facturing district, where a supply of coal is of such vital 
