.Y 
380 Correspondence. 
roofless cave (excepting where it is covered by a sea-worn arch), 
might lead to a better understanding of the origin of deposits in 
caves. Here no fresh water could ever have percolated to any 
extent, as the High Tor is surrounded by low ground. 
On the footpath between Cromford and Bonsall, I have seen 
smoothed surfaces and markings on the limestone rock, which, if 
they are not glacial, are probably as much so as many phenomena 
which are attributed to icebergs, if not to sub-aérial glaciers. IL 
believe the rock is called the Bloody Stone. D. MackintTosH. 
PERMIAN STRATA IN THE VALE OF CLWYD. 
To the Editor of the GnoLoGIcaAL MAGazINE. 
Srr,—I have recently observed on the eastern side of the head of 
the Vale of Clwyd, a small exposure of Permian strata, intervening 
between the Bunter Sandstone and the Mountain-limestone. The 
Permian is not marked on the map of the Geological Survey as ex- 
isting anywhere in the Vale of Clwyd; and as its occurrence gives 
evidence of even still greater antiquity to an important erosion of 
the Mountain-limestone of North Wales than that mentioned by 
Professor Jukes in your last number, I send the accompanying sketch- 
section for publication in the Magazine. 
W. . Road between EB Upper road 
Lianfair “2 Pentre Glyn S to Llan- E. 
Chapel. Af, & Caer Owen. & degia, 
Vale of Clwyd. 
1. Bunter Sandstone, dip 20° to | 3. Purple Shales, Sandstones, | 5. Slates and Grits. 
30° N.W. &e. Dip. 42°S.W. 6. Denbighshire Flags. 
2, Permian Marls. 4. Carboniferous Limestone. 7, Upper Silurian. 
Dip about 40° S.W. 
SKETCH-SECTIONS NOT DRAWN TO SCALE. 
On the Geological Survey Map, sheet 74, the Mountain-limestone 
near Lianfair Chapel, forming the eastern boundary of the vale, is 
represented about a third of a mile in width. Itis, however, between 
Pentre Celyn and Caer Owen, much narrower; the whole of the 
space to the west of the road, and part of that to the east, consisting 
of an alternation of red marls, variegated shaly beds and purplish 
sandstones, and pebble beds, with some impure concretionary lime- 
