LITMIR.BIZ

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on to the north side of Longendale. A swift torrent flowing down the western slope of Kinderscout starts as the Kinder Downfall, which is the only considerable waterfall in The Peak (Plate V, see here) Two rivers, the Etherow and the Derwent, are the centres towards which many of these streams converge. The spacious valleys of these rivers have steep sides with the usual step-like grit features at successive levels crowned by magnificent scarps. In each case the left side rises more abruptly, forming a continuous feature of great grandeur only slightly broken by notchlike cloughs. On the right side the valley sides are less abrupt and are deeply dissected by larger valley-like cloughs.

      In the northern outskirts of the drainage basin of the Derwent much of the Kinderscout Grit has been removed and has left the underlying shales with minor grits exposed over extensive areas. These are occupied by moors and mosses lying some 500 feet lower than The Peak. They also are redeemed from monotony by the presence of attractive tributary valleys, spacious but steep-sided.

      East of the Derwent the outcrops of the Kinderscout Grit continue south as the East Moors. These are defined on the west by a series of prominent scarps (Derwent, Stanage, Froggatt and other Edges) overlooking the main valley. They dip at a steeper angle than that already seen in the north but carry a similar series of dip slopes and scarps. Here, however, the continuity of the latter is interrupted by the transverse folds already mentioned. They give rise to structural and surface features like those described above in detail for Matlock Moor.

      In the West Moors, between Buxton and Macclesfield, the geological structure of the district reaches its maximum of complexity in sharp north-to-south folds crossed by minor ones trending west to east, thus producing an area of intermingling types of scenery like those already described but on a smaller scale, surrounding or enclosing in their synclinal hollows patches of lowland types due to the presence of pockets of Coal Measures and even of Triassic rocks.

      One more element in the make-up of the district remains to be mentioned. The Edale Shales which lie between the limestone and the grit have a maximum thickness of some 1,000 feet. Under normal circumstances it should crop out as a relatively broad zone between the limestone uplands and the moorlands. Owing to cross-folding and faulting, especially in the west, the zone is broken into a number of separate patches which give origin to the gracious landscapes of Darley Dale, Edale, overlooked by Mam Tor (Plate VIb, see here), and Hope Dale. The more extensive patches lie outside the area to the south and south-west.

      THE WORLD UNDERGROUND

      Reference has already been made see here to the formation of caves as a common feature of the limestone area of The Peak. The exploration of these caves under proper auspices is a challenging form of recreation for the physically fit, exciting but rigorous, while many of them are of special scientific and archaeological interest. Some of the larger and more spectacular examples are exploited commercially, like the famous Blue John Cavern (strictly the Blue John Mine), the Peak and Speedwell Caves and the Treak Cliff Caverns (Plate 2b, see here), all in the Castleton district, and are an unfailing attraction for the general sightseer, though they are not quite so impressive as those of Cheddar.

While the processes by which caves are formed are not disputed, opinions differ as to the conditions necessary for the processes themselves to operate. As already explained, caves mainly owe their origin to water action, either as a solvent in the limestone or as an agent for the transporting of rock material by which the beds of underground streams are scoured. The relative importance of each of these forms of water action doubtless varies with local conditions. Authorities hold different views, however, as to where, in regard to the underground water, the cave-forming processes take place. Some maintain that caves originate and develop above the water-table within what is termed the “vadose” zone, i.e. the zone between the surface and the level of saturation, within which water moves downwards by gravity. This view implies that water percolating downwards from the surface will dissolve almost all the calcium carbonate it can hold before it reaches the water-table. Others have shown that many caves must have originated below the water-table in the “phreatic” or water-logged zone. Regarding this issue much depends on such factors as the extent to which solutional activity may continue below the water-table and the nature of water movement resulting from pressure exerted in the phreatic zone. It is likely that each of the theories is applicable to certain caves. In many cases, since there is ample evidence in the Peak District, as elsewhere, of past changes in the level of the water-table, it is reasonable to favour a compromise involving the application of both theories.

      Although the phenomenon of limestone caves has been widely studied in many parts of the world, there is scope for much further investigation. For this the Peak District presents an obvious field. As Dr. G. T. Warwick has pointed out, the need is for a careful examination of particular caves, including the basic work of surveying them, without which detailed study cannot be advanced. In this connection the recent work of Dr. Trevor Ford on the Treak Cliff Caverns is to be welcomed not only for its intrinsic value but as pointing the way for further investigations.

      Caves are seldom found in the Millstone Grit and when they do occur they generally take the form of narrow fissures resulting from the displacement of large blocks of rock. The Kinderlow Cavern on the western edge of Kinderscout is of this type, where a large but narrow block of gritstone has slipped from the main mass, yet still leans upon it, so forming a roof. The Kittycross Cave in Bradwell Dale, though primarily a limestone cave, is partly developed in decomposed toadstone.

In the limestone area it is important to distinguish between natural caves on the one hand and the underground passages and chambers resulting from lead-mining operations on the other, although the latter have often been the means of revealing some of the deepest and most impressive of the natural caves. A good example is the Bottomless Pit in the Speedwell Mine at Castleton which is due to the solution of lime-bearing minerals, mostly calcite, surrounding the ore body. Again, in the Blue John Mine and the Treak Cliff Mine the search for lead resulted in the discovery of extensive natural chambers. In fact many of the more intricate caverns now exploited as show-places owe their accessibility to former mine workings.

       Fig. 6. Distribution of the principal caves in the Peak District. (Based on G. T. Warwick)

      In the Peak District the distribution of caves is by no means haphazard. The majority tend to occur around the margin of the limestone in the neighbourhood of streams which flow on to that rock from the higher gritstone areas around it (Fig. 6, see here). Such streams, on encountering the limestone, have developed considerable underground drainage, the more so since much of the limestone, especially along the northern and western margins, is of the reef type (see here), which is relatively pure and highly soluble. Under such conditions there is a marked concentration of caves in particular districts. Of these the Castleton, Bradwell, and Eyam-Middleton districts in the north, the Dove-Manifold area in the south-west and the Matlock-Wirks-worth district in the south-east are the chief. In the interior of the limestone area caves occur along some of the valleys such as the Wye and the Lathkill.

      Most of the caves, except some in the Castleton group, are situated on the valley slopes or near the present stream level. High-level caves like the Harborough Cave near Brassington, at over 1,000 feet, are seldom found though they are of interest in indicating that ages have elapsed since the water-table stood at such an altitude and they must therefore be of great antiquity. Eldon Hole and Nettle Pot on opposite flanks of Eldon Hill are the only Derbyshire pot-holes, i.e. caves with a vertical pitch, like Gaping Gill in Yorkshire. Eldon Hole is 120 feet long and about 20 feet wide; it reaches to a depth of over 180 feet where it opens into two distinct caverns. Many of the Peak District caves have yielded significant palaeontological and archaeological remains. Thus, from a fissure in the

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