12 SKETCH OF THE GEOLOGY OF DERBYSHIRE. 
towards the S. its elevation gradually becomes less, and the tract of 
country occupied by it less conspicuous, till it is entirely concealed by 
the new red sandstone at Morley, four miles N.W. of Derby. Its 
boundary will be approximately marked by that of the limestone as 
far S. as Wirksworth, whence it runs S.W. to Milford and Little 
Eaton. W. of this boundary, however, there is an outlier of it, as 
already indicated, lying in a depression of the shale, and on which 
the villages of Callow and Kirk Jreton stand. This isolated patch is 
surrounded on every side by shale, and is about three miles long from 
N. to S., and about 14m. across. Its beds dip on all sides towards 
its central portion.—(See sections Nos. 2 and 3). The diminution 
in consequence of the millstone grit towards the S, does not seem 
altogether due to its diminution in elevation, but in part to a gradual 
thinning out and diminution of the formation itself, which is in ac- 
cordance, I believe, with what is known of it in its course to the N. 
Before leaving this formation, there is a circumstance connected with 
this eastern part of it which demands our attention, which is, its being 
broken through in two places, and the inferior rocks brought up to 
the surface. These two places are Ashover and Crich. On leaving 
Matlock to go to Chesterfield, we perceive at Matlock Bridge the 
limestone dipping to the E. and passing under the shale which com- 
poses the next hill. This hill is capped with gritstone, which like- 
wise dips to the E. but, instead of plunging regularly beneath the 
coal-field, in about three miles the wood reaches an abrupt escarp- 
ment, where the gritstone may be seen dipping rapidly to the W., and 
overlooking the valley of Ashover. This lovely valley is formed by 
an amphitheatre of gritstone hills opening to the S. and dipping from 
the valley on either hand. Beneath the gritstone, which, as usual, 
forms a very steep slope, with projecting crags, comes the more gra- 
dual outline of the shale, while the middle of the valley is occupied 
by a green ridge of limestone. The beds of this limestone dip from 
the centre on every side, at a moderate angle, passing underneath the 
shale, which, by a similar dip, underlies the gritstone. The heights 
of gritstone have an elevation of about 500 feet above the little river 
Amber at the bottom of the valley, which is there itself 500 feet 
above the sea, and which, to complete the loveliness of the place, and, 
as it were, to render it an epitome of the Derbyshire district, cuts 
transversely across the limestone ridge, producing the usual beauties 
of a limestone dale in miniature, and engrossing the toadstone for a 
considerable distance. Many lead veins traverse the limestone, 
which, upon the whole, preserve the same laws of direction that have 
