260 Mr. Farey's Account of the Slips in Strataf <5#c. 



the important and contested questions, respecting the origin, 

 and mode in which Valleys were excavated and Jormcd. 



It must not be inlerred, that high and precipitous Rocks 

 and Cliffs are peculiar to or confined to the class of Vallevs 

 of which I have been speaking, since the sides of the wide 

 Vallevs, also, abound with Rocks and Clifls, some oF them 

 highly picturesque and beautiful, Hut such Rocks seldom 

 continue far, without the intervention of grassy or culti- 

 vated slopes, such as the sides of Valleys usually present, 

 in districts where no durable or permanent Rocks exist in 

 their strata : whereas, in the narrow Valleys above, such 

 slopes, or interruptions to the continuity of the Cliffs on 

 each of their sides, are rare, and in some instances do not 

 occur at all, within the distances which 1 have nam-^d. 

 The Grit-stone Rocks of this district, seem particularly dis- 

 posed to appear and disappear repeatedly on the surface at 

 their edges, or in tracing their Bassets through the country; 

 and except of the 1st or lowest Grit Rock, it is a rare thing 

 to find a continued Grit-stone Cliff of any length : some 

 of them, indeed, are so disposed to moulder and fall, on 

 exposure to the air, rain, frost, &c. that Cliffs of such 

 Rocks are never seen ; but where Slips or slidings have 

 happened, in comparatively modern times, of which there 

 are numerous and striking examples in Derbyshire, parti- 

 cularly in the Shale and shale Grit districts ; and as it seems 

 of the uimost importance in Geological researches, to di- 

 stinguish betueen Cliffs or Facades of equal antiquity with 

 the Valleys themseRes, probably, or such as have originated 

 'with, or been increased by, subsequent and sudden Slips*, 

 or by the gradual and recent undernnning of currents of 

 the Brooks and Rivers, 1 shall here give a 



List 



* Since the above wss written, I have read with some surprise, pages 61 

 and G2 of the recent Translation of M. Werner's " New Theory," on the 

 subject of Miner.;! Veins, wherein the phasnomcnon of SHps, as nbove, is 

 described, and it is gravely maintained, that such, happening " in rainy sea- 

 sons," have opaed the fissures for Mineral Veins (to be afterwards filled, I 

 supposed); as though the conchoidal fracture of a Slip from an adjoining 

 Hill, close pressed and ground by the moving load of softe.ud Earth, had 

 any relation to a rake'" vein ! 'fhis is not however solely relied on for the 

 opening of Veins; l)vit we are informed (p. 48), that while the beds of the 

 Mountains were "at first wet, and possessed little solidity," the mass" yielded 

 to its weight," '■ sunk and cracked," " falling to the/>Tf side;" now, notwith- 

 standin"-the parade of mathemntical definitions and preparations, at pages 

 88 and 89, I would venture to ask any one who knows Derbyshire, and the 

 large rake Veins wh'.ch cross the comparatively flat districts, that lay between 

 BradwcU and Tide well or Wardlow, between Sheldon and Monyash, be- 

 tween Winster and Bonsai, &c. which is the free iide in any of these cases ? 

 or what sort of an action of Iheir mvrt u-i'ighi it must have been, which 

 caused such immense lumps of Limestone to start a few feet asunder, in so 



many 



