218 A POPULAR SKETCH OF THE 



stuck full of pebbles of all sbapes and sizes, driven pell raell toge- 

 ther, without the slightest order or arrangement. These pebbles are 

 almost wholly gritstone and limestone ; and in some of the masses 

 the calcareous matter has diffused itself sufficiently to bind the whole 

 into a compact conglomerate, like that so often seen in the lower 

 part of the new red sandstone.* It is, however, certainly a mere 

 superficial diluvium, in which we can trace the action of the denud- 

 ing forces that have brought down these ruins from the hilly region 

 to the north. Over all the undulating country between Ashbourn 

 and Derby, the diluvium consists for the most part of a light yellow 

 sand, sometimes forming a soft sandstone and containing beds of 

 pebbles. These pebbles are small, much rounded, and almost 

 wholly quartz, a piece even of mountain limestone being rare. I 

 never, among this gravel, too, could find or hear of any one finding 

 a chalk flint. This is the more remarkable, because chalk flints, 

 sometimes of large size, are scattered over the surface in considera- 

 ble abundancet ; and boulders of mountain limestone may likewise 

 be met with. These facts seem to point to two distinct periods of 

 diluvial deposit, the quartzose gravel being the oldest. As we 

 descend towards the valley of the Ti - ent and the country becomes 

 more level, this diluvium gets less and less sandy, till it is at last 

 almost wholly a mass of quartz pebbles. These pebbles are firmly 

 compacted together, seemingly by the pressure of the mass ; a 

 sharpish blow is required to detach one, when its shape is generally 

 left in a thin matrix of fine sand, which fills up the interstices 

 between the pebbles. An occasional bed of sandstone, some inches 

 thick, also occurs, thinning out within a few yards, and the whole 

 mass has a semi-stratified character, the pebbles lying horizontally 

 in regular lines. This gravel may be seen at Morley Brook, three 

 miles N. E. of Derby, whence it may be traced at some height on 

 the flanks of the Derwent southwards to the Trent. In the Castle- 

 fields south of Derby, it contains more limestone pebbles than are 

 seen in it elsewhere. On the right bank of the Trent it is very 

 abundant, gravel-pits at Repton being thirty or forty feet deep in it 

 with perpendicular walls like a stone quarry. Whence the immense 



* On my first visit to this place, I was completely deceived into the belief 

 that this hill was a new red sandstone conglomerate ; and it was only on a 

 second visit and seeing a larger portion exposed, that I perceived its diluvial 

 character. 



f About four miles south of Ashbourn, I one day found a chalk Hint, con- 

 taining a large inoceramus, one of the most characteristic shells of the chalk 

 formation. 



