The Medals of Creation, Volumes 1 and 2 / First Lessons in Geology and the Study of Organic Remains

by Gideon Algernon Mantell

NOTES FOR A GEOLOGICAL EXCURSION BY CROMFORD, UP BONSAL VALLEY, BY VIA GELLIA, TO MIDDLETON MOOR; RETURNING BY STONNIS.

This excursion will present many objects of interest, and one day at least should be devoted to the examination of the different localities pointed out in the following notes.[812] To Cromford, and then take the road that leads through Bonsal vale. A fine range of limestone on the right, and a sparkling stream (Bonsal-brook) on the left. On the banks of this brook there is a manufactory of mineral colours (Pooley’s) well worthy a visit. But before we reach this establishment, there is an opening on the hill side where the strata are exposed, and a bed of Trap is seen beneath the limestone; near this place specimens of fluor, calc-spar, &c., that have been thrown out in forming the excavation, may be collected. From beneath the trap a warm spring issues and flows into the neighbouring brook.

[812] Benjamin Froggatt should be engaged to conduct the pedestrian; and a carriage party would also do well to place themselves under his guidance.

Proceed up the road leading to Via Gellia, and through a valley flanked with high ranges of limestone and dun-stone. On the right, is the beautiful cascade previously mentioned, near Dunsley. This valley is a celebrated botanical region, for several species of plants which are of great rarity or unknown elsewhere are here met with. At the direction post, turn to the left up the steep hill that leads to Middleton Moor. On each side numerous fossils of the mountain limestone may be collected from the blocks lying on the flanks of the hill. Views splendid in picturesque scenery and of a highly interesting geological character are obtained as we ascend. On the summit of Middleton Moor, which is from 1,300 to 1,400 feet above the level of the sea, a most extensive panoramic view of the surrounding country may be obtained. The geological map will enable the observer to identify the crags of Charnwood Forest, the High Peak, &c. &c. Almost every part of the Moor is studded with the disused shafts of exhausted mines, and which are so carelessly covered over as to be extremely dangerous, and the visitor must bear this caution in mind; for the heaps of stone placed at irregular intervals on the hill, and which tempt the geologist to seek for specimens, are for the most part piled over the openings of deep shafts.[813]

[813] My son narrowly escaped being drawn in by a heap of stones which gave way under his feet, and suddenly disappeared in the chasm below. In rambles of this kind in a mining country, the young geologist must, therefore, be upon his guard, or he may be engulphed with masses of limestone in some deep chasm, and his bones, incrusted with stalactite, form an ossiferous breccia, that in future ages may perplex some collector of organic remains to determine its relative antiquity!

Pass on by Worksworth, to the quarries of mountain limestone, where the encrinital marble, so largely employed for side-boards, chimney-pieces, &c. is procured. Near the approach to the entrance of the quarry, an instructive example of curved strata of limestone is seen on the left; and on the right, a fine vertical artificial section. On the weathered surface of the left side of this entrance, and on the face nearest the quarry, good specimens of the stems I and ossicula of the usual Derbyshire crinoidea may be extracted ([p. 284]) from the layers of reddish limestone; and good blocks of the marble may be selected. Large spirifers can be procured from the limestone in these quarries; the quarry-men often have specimens. On the right hand of the entrance, layers of flinty slate (called partings of black bind by the miners) occur between the beds of limestone. In a field near this quarry, on the left of the road leading to Cromford, where some mining operations are going on, blocks of the stone called chert have been thrown up, and often contain beautiful examples of the pulley-stones ([p. 285]), or siliceous casts of the stems of the crinoidea. A large collection of fossils may be gathered in the localities above mentioned.

We now drive to the escarpment of millstone grit at Stonnis, called Black-rock, whose pine-clad summit forms so conspicuous an object in the view from Crich Hill; it is about a mile from Cromford, and overlooks Matlock Dale.

On the right of the road, the refuse workings of a mine cover the side of the hill; among which some specimens of spars or minerals may perhaps be found.

VIEW FROM STONNIS.

But the grand attraction of Stonnis is the view of Matlock Dale and the surrounding mountains, obtained from the verge of the precipitous escarpment of sandstone rocks, under the knoll of pines. It is, indeed, a scene of transcendent beauty and magnificence, and is said, by one who has ascended every mountain top and traversed every ravine and valley in this district, to be unrivalled.