TIDESWELL is a very good centre for those who wish to learn something of the geology and scenery of the mountain limestone and the igneous rocks associated with it. These brief notes are not intended to be anything in the nature of a sketch of the Geology of the district. Their purpose is merely to point out some of the interesting rocks easily accessible from Tideswell.

One of the most noticeable features of the district is that the stone walls, especially when the fields are small, obtrude themselves on the eye of the visitor and spoil the scenery. But on Bradwell Moor, Old Moor, and Eldon Hill, the fields are large, the air is invigorating, and on a fine day the views are charming. The slightly undulating character of the limestone tract, trenched here and there by deep gorges may be studied, and the outlines of the yoredale sandstone and millstone grit hills bounding the northern area of the limestone may be seen in the distance.

Those who prefer valleys to moorlands should visit the valley of the Wye in Millers Dale and Monsal Dale, Cressbrook Dale, Bradwell Dale, Middleton Dale, Tideswell Dale, or Brookbottom, and learn how slow but sure is the action of streams in cutting out these gorges.

Castleton with its caverns is within easy reach and well worth a visit. The entrance to Peak Cavern is very fine.

In the Speedwell Mine the visitor is taken in a boat along an artificial level of nearly half-a-mile in length. He then enters a natural cavern with a very high roof. The water falls with a deafening roar into the “Bottomless Pit”, the bottom of which is about 85 feet below the platform. The Blue John Mine is also partly natural and partly artificial. It consists of a number of caverns connected by passages. The walls of the caverns at once remind us of the sides of some of the gorges, and prove their common origin, viz: the chemical action of water dissolving the limestone and the mechanical action of the same agent.

The popular notion of a geologist is that he is merely a collector of fossils, and that sometimes he is really in search of lead or gold. A truer estimate is that he is “studying stones”, or “running up hill and down dale, knapping the chuckie-stanes to pieces wi' hammers, like sae mony road makers run daft - to see, as they say, how the warld was made”. The fossil collector will find specimens in the neighbourhood of Castleton, in the quarries at Cave Dale, Pindale, near the Speedwell Mine, and on Tray Cliff. Corals are numerous in a quarry on the carriage road from Millers Dale to Tideswell just after leaving Millers Dale village. In the old marble quarry in Tideswell Dale and on the opposite side of the valley on the carriage road three species of corals, viz.: lithostrotion junceum, lithostrotion irregulare, and Dibunophyllum have been found.

In the quarry close to Anchor Inn, at the six lane ends, are numerous fossil shells. In a quarry at Peep o'Day, Litton, the limestone immediately above the volcanic tuff is rich in fossils, crinoids, brachiopods, polyzoa, lamelli-branchs, gasteropods and corals of cup form and in bunches and beds.

Tideswell is near the centre of the northern area of volcanic activity of the county. Whilst the mountain

limestone was being quietly deposited on the sea bottom small submarine volcanoes poured out their molten lavas or ejected their fragments of volcanic detritus or tuff over the sea floor. At a later period, long after the limestone had solidified, hot igneous rock pushed its way up through fissures and spread between the beds of limestone, or the different lava flows, but never reached the surface of the ground.

Owing to the wear and tear of the rocks proofs of this former volcanic activity are exposed to view, and may be seen near Tideswell.

One of the most interesting exposures of an interbedded tuff is at Litton, in the roadbank near Peep o'Day. It is about 150 or 200 feet thick, and consists of alternations of fine and course laminæ, of a green and yellow colour with pebbles of coralline limestone and, blocks of compact igneous rock up to eighteen inches in length. It may be followed down to Cressbrook Dale, and in the opposite direction under Litton Edge, and across the road between Tideswell and six lane ends.

One of the best exposures of a lava stream may be seen in Millers Dale on the lowest road to Tideswell, a few hundred yards after leaving Millers Dale village. The rock is dark, contains numerous steam holes, some of which are filled with carbonate of lime, and give the rock a spotted appearance. This is the lower lava stream of the district, and is seen again in Monks Dale, and in Millers Dale near Chee Tor Tunnel. The upper lava, which is about 150 feet higher in the limestone beds is seen in Priestcliffe lane and at the top of Knott Low near Millers Dale Station, and may be traced for several miles in the direction of Taddington and Chelmorton Low.

To students of igneous rocks, the old marble quarry in Tideswell Dale cannot fail to prove interesting. A fault

runs across the valley near the sewerage farm, and on both sides the igneous rock abuts against the limestone beds which are higher in the series. About half-a-mile further south there is another fault. It crosses the middle road where the road makes a sharp bend, passes down a small gully and runs up a depression south of the marble quarry. The limestone between these faults contains several flows of contemporaneous lava and volcanic mud. The area has been carefully worked out by the author, and it has been found that the intrusive rock or sill has pushed its way between the beds of limestone and the lava flows. This sill is from 60 to 70 feet thick, and cuts across the lower parts of the lava, but sometimes rests upon the limestone below. The marble in this quarry is a limestone which has been baked by the hot intrusive rock. On the opposite side of the valley the baked limestone, the indurated or baked clay now in small columns, and also the lava below the intrusive rock, may be seen. The lava above the sill is found on the hill slope on the right hand side going towards Tideswell. The intrusive rock or dolerite has been quarried for road metal.

Another of these intrusive masses covers a large surface near Potluck, and large blocks of it are found in the fields. A third mass occurs at Peak Forest, in Dam Dale. The alternation of the limestones above the igneous rock extends for some feet and forms an interesting study.

We now bring these brief remarks to a close, and express a hope that they may not only lead visitors but also some of the inhabitants of Tideswell to examine for themselves some of the interesting features of Geology of the immediate vicinity of Tideswell.