THE GEOLOGIST. 



9 



Thus Professor Buckman, iii a very interesting paper on the 

 Combrash* in the neighbourhood 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 " & 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 due cultivation 

 of the soil. In general the deepest drains do not penetrate beyond 

 the mere superficial deposits immediately overlaying the stratum 

 on which they repose, though very often, where the surface soil is 

 thin, the former is cut through to a greater 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 pui-poses, 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 largely 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 



