448 On the Agricultural Geology of England and Wales. 



out in very nearly their origfinal horizontal position, they appear 

 Tinder their original mineral aspect of clays and limestones, as 

 soft and incoherent as our tertiary and newer secondary strata. 

 In Devonshire they are so much indurated by contiguity to the 

 granite of Dartmoor, as to assume the texture of the older slates 

 and sandstones, with which they were till lately confounded. This 

 altered condition is the form under which they most commonly 

 occur on continental Europe ; so that the old red was long- sup- 

 posed to be peculiar to the British Isles ; and the first inquiry 

 of a foreign geologist in England was for the gres rouge antique. 

 In Herefordshire these rocks appear in a state intermediate be- 

 tween the condition of the same strata in Russia and in Devon- 

 shire. Soils derived^ from the two extremes of these conditions 

 must differ as much as raw clay differs from ground bricks and 

 tiles. 



6. Agricultural geology should discriminate between soils com- 

 posed exclusively of the materials of the rocks on which they rest, 

 and those in which the materials have been derived from various 

 strata and blended by aqueous transport. 



7. The investigation of the sources whence materials for build- 

 ing, draining, and road making may be obtained, of the best 

 quality, and at the cheapest rate, is a department of geology of 

 no small importance to the farmer. It will often instruct him 

 how, on the one hand, he may obtain, under or near to his own 

 land, the very substances which he is bringing at a great expense 

 from a distance ; and, on the other hand, how, by means of rail- 

 ways, they may be brought twenty or thirty miles at a cheaper 

 rate than from nearer sources of supply whence he is carting 

 them with his own horses. 



8. To these, which may be considered the direct influences of 

 geological conditions on the agricultural capabilities of different 

 districts, we may add the indirect influence, arising out of the 

 distribution of those formations which affect the demand for the 

 produce of the soil, by concentrating on certain areas large masses 

 of population not employed in agriculture. A poor soil in the 

 vicinity of Manchester, Leeds, Sheffield, Birmingham, and the 

 other great manufacturing towns which are congregated on or 

 near to the coal measures, will be of greater value than a better 

 soil in a district thinly peopled and remote from markets. 



Present imperfect state of Agricultural Geology. — Such are 

 the questions which agricultural geology is required to answ^er. 

 To some of the most important of them, which relate to the dis- 

 tribution of soils, it is unable, in its present state, to give more 

 than very imperfect answers, because the greater part of the data 

 necessary for their solution are yet uncollected. 



For the purposes of agriculture, geological investigations should 



