456 Geological Society. 



large portion of the turf having recently been removed, the surface of 

 the rock is now seen to be scored with parallel lines, precisely similar 

 to those observed in other places, and described by Sir J. Hall, Dr. 

 Buckland, &c. And in this case, although the surface of the ground 

 is very unequal, and the dip and bearings of the denuded strata vary 

 considerably, the direction of Ithe markings is uniformly from N.N.W. 

 to E.S.E. 



3. Hebrides, and Mainland of the West Coast. — Pitchstone, a 

 mineral not previously found ia Scotland in association with the more 

 recent stratified rocks, has been discovered by Professor Sedgwick 

 and Mr. Murchison in two places ; forming portions of trap dykes, — 

 one of which cuts through the lias and inferior oolite at Carsaig Mull j 

 the other traverses the cornbrash and forest marble, at Beal near 

 Portree in Skye. The identity of the various secondary strata in the 

 Isles of Mull, Skye, Pabba, Saalpa, Rasay, &c., is now established by 

 the numerous organic remains which they have been found to contain, 

 many of which belong to new species, but the greater number are well 

 known as characteristic fossils of the oolitic formations in England. 



The former vast, and perhaps continuous, extent of these deposits 

 on the western coast, is further rendered probable, by their having 

 been observed by Professor 5iedgwick and the author, on the N.E. 

 coast of Mull, at and near Tobermory ; and at Applecross on the west 

 coast of Ross-shire. In the latter place, lias-limestone, similar to that 

 on the opposite shores of Skye and Rasay, rests conformably upon the 

 new red conglomerate ; and as the same fact had been previously 

 remarked on the east coast, near Cromarty, evidence is thus af- 

 forded that the members of the oolitic series of Scotland, generally, 

 were of subsequent formation to that great mechanical deposit ; being 

 lodged, apparently, in the basins or undulations presented by its surface. 



A letter was read from G. W. Featherstonhaugh, Esq. to W. H. 

 Fitton, M.D. P.G.S. &c. &c. j containing an account of an excavation 

 in the chalk at Norwich. 



The writer, having learnt that an extensive cavity in the chalk of 

 Heigham Hill near Norwich, had been discovered about four years 

 ago, in consequence of the workmen who were digging a well, having 

 suddenly sunk into a vault, examined the place ; and he describes the 

 excavation as consisting of various galleries, (a plan of which is an- 

 nexed to his letter,) of about eight feet in height, from two to five feet 

 in breadth, and occupying a total length of 4600 feet. He conceives 

 that the object of this laborious work, was to extract the flints, which 

 were used in great quantity in the construction of the ancient build- 

 ings and walls of Norwich j since the nodules of flint have been 

 almost entirely removed from the catacombs, while the chalk itself 

 is left. And he states in support of this opinion, that upon re-opening 

 the original entrance, which had been blocked up by ruins, the date 

 1571, with the name of one of the workmen, was found written on 

 the side of the cavern : — a year which corresponds with a period, 

 when the walls of the town are known to have been repaired with 

 flints, and various buildings formed of them, 



ROYAL 



