THE GEOLOGIST. 
9 
Tbns Professor Buckmaii, in a veiy interesting paper on the 
Conibrash* in the ueighbourhood of Cirencester, in Gloucester- 
shire, has shewn the varying value of three different brashy soils, 
belonging to the Combrash, Great oolite, and Inferior oolite 
respectively ; the first of which yields the most abundant produce. 
He also points out how "a successful farmer near Cirencester 
had converted a 'brash farm,' (usually a term of reproach) into one 
of the most productive ones in the district." Hence we may infer 
the great practical advantage of sufficient geological and chemical 
knowledge in all farming operations. 
The drainage of lands is of no little consequence, both as regards 
the healthy condition of a neighbourhood, and the duo cultivation 
of the soil. In general the deepest drains do not penetrate beyond 
the mere superficial dejDOsits immediately overlaying the stratum 
on which they repose, though very often, where the surface soil is 
thm, the fomier is cut through to a gi'eater or less extent. In 
either case, it comes within the province of the Geologist to 
determine the variable dip, thickness, and structure either of the 
surface soil or substratum, as it affects the question at issue. 
Allusion here might reasonably be made to the valuable 
properties of rocks for some other economical purposes, such as 
lithography, lime, bricks, and roads ;f in many cases they even 
form an available and excellent manure, some of which, as the 
Crag in Suffolk, is lai-gely exported for this purpose. 
Much of this has been perhaps discovered without the aid 
of Geology, but a good practical Geologist cannot fail to enlarge 
the sphere of observation, pointing out fresh localities, which 
his well-practised eye and scientific experience alone could have 
detected, besides giving other valuable information in relation to 
various points which would escape the notice of a superficial 
observer. 
We have only briefly alluded to these subjects which relate more 
* Proceedings of the Cotswold Naturalists' Club, vol. i. 1853. 
t In addition to these may be enumerated the cement stones in the London clay, 
and the manufacture of sulphuric acid from the pyrites contained in this formation ; 
the value of ironstones generally both in the Inferior oolite and Lias, and in the 
Carboniferous series ; the importance of the alum shale in the Lias at Whitby, and the 
manufacture of Carbonate of Magnesia from the Mountain limestone of Ireland. 
C 
