Oil the Agriciiltural Geolo(jy of England and Wales. 450 



The results of such an examination have convinced us, that the 

 views announced in the paper on the Geoh:>gy of Norfolk, before 

 alluded to, are not merely local truths, but that, in most cases, 

 the variations in the soil are more dependent on the operations 

 which caused the accumulation of the erratic tertiaries during a 

 period of gradual submiergence, and their denudation during a 

 period of re-elevation at the close of the tertiary period, than to 

 the rock formations ; the soil itself being, in most cases^ an 

 aqueous deposit, throvi^n down unconformably on the denuded 

 surface of the erratic tertiaries, or of the older strata when the 

 denuding action has reached them. We do not enter here into 

 the question when this unconformable deposit was formed — 

 nor of the nature of the agencies by which it was formed — 

 whether it was the effect of the last wash of the sea on the emerg- 

 ing land, or whether, as there is good reason to believe, it was 

 the result of subsequent operations after the desiccated bed of the 

 sea had existed a considerable time as dry land. These are 

 questions of greater theoretical than practical interest. The 

 existence of such a deposit is the important agricultural fact. The 

 dependence of the variations of soils on contours, and the indica- 

 tions these afford respecting the situations in which the best, that 

 is, the deepest, driest, and most mixed soils are to be found, will 

 be nearly the same, whether an interval elapsed between the 

 emergence of the land from beneath the erratic sea and the 

 formation of this deposit, or whether the two events were con- 

 temporaneous. 



Influence of physical features on the distribution of the erratic 

 tertiai'ies. — The distribution of the erratic tertiaries has been in- 

 fluenced by the general configuration of the great features of the 

 land, which were established before the submergence under 

 which the erratic deposit accumulated ; that is to say, by the 

 position and direction of the mountain chains and ranges of hills. 

 These were the results of disturbing forces, by which the strata 

 have been fractured and tilted up ak)ng different lines at different 

 periods. 



The mountains and hills of England may be thus enumerated. 

 In the extreme north we have the porphyritic ridge of the Che- 

 viots. A little further to the south-west are the mountains of the 

 English lake district, or Cumbrian chain; and, still further to 

 the south, those of Wales ; both consisting of silurian and older 

 rocks, of various mineral character, associated with igneous rocks 

 as various in their composition. Down the centre of England 

 extends the great Penine chain,* which ranges from the Tyne to 

 the Trent, and is composed of carboniferous limestone, millstone- 



* The Alpes Penini of Roman Britain. — See Conybeaie's ' Outlines/ p. 365. 



