THE GEOLOGIST. 
JULY, 1858. 
THE IRONSTONE-FORMATIO:^ OF THE FOREST OF DEAN; 
WITH A SKETCH OF THE GENERAL GEOLOGY AND 
INDUSTRIAL HISTORY OF THE DISTRICT. 
By De. J. J. W. Watson, F.G.S. 
{Continued/rom page i2G.) 
Millstone Gkit. 
The coal-measures repose conformably on a series of grit-beds, all 
more or less charged with oxide of iron, and measuring together about 
500 feet in thickness. In some places a bed of limestone intervenes 
between the lowest bed and those above, but the general section, in 
descending order, is as follows : — 
1. Coarse red grit-stone, called " The Miner's Farewell Rock." 
2. Light red sandstone, with layers of variegated marls, which, 
although partly indurated in the bed, fall to pieces by exposure to 
the air. 
3. Fine-grained quartzose grit, much charged with iron in the middle 
beds, constituting the " Sandstone Mine Formation." In this group 
there are two thin beds of coarse conglomerate, or pudding-stone. 
Coal Measttees. 
It would be impossible for me to enter into any adequate description of 
this most important part of the Forest geology, without extending this 
article to an undue length. The following summary, therefore, must 
suffice, in the present instance ; although I purpose describing the coal- 
