58 
back down each valley, and throws out a projecting spur 
along each plot of rising ground. This configuration alone 
shows that the one formation rests on the other, without 
the intervention of a fault, and would be conclusive inde- 
pendently of the evidence given by natural sections and 
coal wakings. In the other case, the boundary line is 
straight and shows a marked disregard to hill or valley; 
and this, in the absence of any evidence to the contrary, 
would justify us in looking upon it as probably a fault. 
That Mr. Binney has brought forward any evidence to 
shew that it is not a fault, I cannot see. The boring at 
Brinnington seems to shew no more than this : that if there 
be a fault its throw is there probably small ; and this is 
just the view taken by the Geological Survey (see Memoir, 
already quoted, p. 11). 
You will, I am sure, be glad to give the Society the 
opportunity of hearing both sides of the question, and I 
therefore venture to request that this letter may be read 
before the next meeting. Possibly you may think it worth 
while printing it in your Transactions, as a note to Mr. 
Binney’s paper. — I am, yours, &c., 
A. IT. G&een. 
Geological Survey of Ireland, 
51, Stephen’s Green, 4th January, 1870. 
Dear Sir, — From a copy of the “Manchester Guardian” of 
1st December, 1869, forwarded to me by a friend, I find that 
Mr. Binney has called in question the correctness of the 
Geological Survey maps in representing the boundary 
between the Carboniferous and Permian and Triassic rocks, 
east of Stockport, as a fault, or dislocation of the beds. 
As far as I can understand, Mr. Binney’s argument rests 
upon the fact which he states, that coal has been reached 
below the red sandstone (which he calls new red sandstone, 
but which I believe to be permian sandstone) at Brinning- 
