SKETCH OF THE GEOLOGY OF DERBYSHIRE. 5 
valleys, and this sometimes so frequently, and in two or three places 
so near together, as to make it appear that it must belong to more 
than one bed. At Copt Round, for instance, between Castleton and 
Peak Forest, there is a bed of toadstone found at the summit of the 
hill; it appears again about half-way down, and again in the valley at 
the foot, and under such circumstances as would induce any one, at 
first sight, to suppose it to belong to three separate beds lying one 
under another. On a more detailed examination, however, these 
three pieces are found to unite towards the S. and become one, their 
disunion at Copt Round being produced by two faults. Similar cir- 
cumstances are continually occurring over all this district, producing 
phenomena which it requires the greatest care and the most patient 
and laborious investigation to disentangle and reduce to order and 
connection. For want of this care and labour it was long the com- 
monly received opinion that three separate beds of toadstone existed 
throughout the limestone district, till Mr. Hopkins did so much 
towards giving us better and more accurate information. Over all 
the country about Burton, Tideswell, and Castleton, he has shown 
that only one bed of toadstone is at present known to exist, and that 
its continued re-appearance at the surface is solely owing to faults and 
dislocations.* On approaching Bakewell, however, there are strong 
indications of two beds existing at Fin Copt Hill, near Ashford; and 
this is certainly the case in the valley of the Lathkill, as mentioned in 
the preceding part of this paper. On passing towards Winster and 
the S. part of the limestone district, two beds have been sunk through 
at Snitteron, and may be traced along the ridge between Winster 
and Wensley. I believe, also, that the toadstone in Masson Lowe 
and at Matlock High Torr belongs to two beds, although Mr. Hop- 
kins gives an explanation of these, as also of Fin Copt Hill, on the 
supposition of one bed only. It is certain that all this district is very 
much broken by faults, which tend to complicate the phenomena very 
much, and render their complete explication a work of time, as well as 
of labour and sagacity. The continued storing of all the facts 
gleaned by mining operations will be necessary, and those facts can 
only be thoroughly arranged and inyestigated by some one who, like 
Mr. Hopkins, shall have been accustomed to the searching out of 
simple principles from a mass of complicated details. The toadstone 
is seen on the extreme southern border of the limestone, at the back 
of Hopton Hall, on a level with the shale, which sets in immediately 
* See sections 1 and 2, 
