SIR, 
F ae 3] 
I HOPE you will excufe the liberty I take in pointing out 
an error which occurs in your remarks on coal-mines, in the 
fecond volume of The Tranfattions of the Royal Irifh Academy, 
At page 161, it is faid, “ In England beds of coal of lefs than 
“ two feet and an half. in thicknefs are judged not worth 
“ working ;” but I affure you that in this neighbourhood we 
-work much thinner feams and at confiderable depths, as you 
may perceive by the fubjoined account of the ftrata at Blakelow 
colliery, fituated about one mile fouth eaft from the town of 
Feet. Inches. 
Macclesfield. 
Non Bo ate 
2. 102 
Eber 
41.285 
aes 
. — 
I 
I 
Sia 
fe) 
Le) 
I 
6 
oO 
NOE SECNGe GN eps 
Clay and gravel. 
Black argillaceous fhale. 
Smut feam of coal. 
Rock. A pale grey fine-grained filiceous grit- 
ftone, containing much particles of mica. 
Grey beds. A foft, lanunated, pale grey grit- 
ftone, containing mica between the lamina. 
Shale. 
Grey beds. 
Shale. 
Grey beds. 
No. 
