Cornwall and South Devon. 337 



ton sands therefore on the east, to Thurlestone in Bigbury 

 bay on the west, they present a synclinal axis : from thence 

 round Bigbury bay to Yealm mouth, and thence in a line 

 drawn to Cawsand on the west of Plymouth sound, it overlies 

 No. 3 killas with a high southern dip : round Whitsand bay 

 it constitutes the far greater portion of the cliffs, in a narrow 

 belt, sometimes thinning out in its deeper recesses, and un- 

 masking the metalliferous killas, which is seen incontrovertibly 

 to pass into and underlie it: this is notably the case in the 

 deeper inlet of Looe bay, where, from Millendreth to near 

 Hannafore point, there is not a vestige of it; Looe island 

 however consists entirely of it, where its beds on the north 

 side dip S. 40°, and thence increase their inclination to verti- 

 cal, and apparently 80° to 85° N. on the south end, in a fine 

 fan-shaped form. 



The eastern cliffs, from West Looe to Hannafore point, 

 where the fish-bearing killas again sets on, afford fine un- 

 broken sections north and south, showing the gradual trans- 

 ition of No. 3 into No. 4, and the indisputable underlie of the 

 former. From Hannafore point to near Hendrasick, No. 4 dips 

 steadily and uniformly to the south and south-south-east at 

 high but varying angles: at Hendrasick cove, a great up-cast 

 fault has brought No. 3 killas into hard collision with the middle 

 beds of No. 4, which, after a variety of strange contortions 

 plunge headlongdownwards after the junction line; but south- 

 ward of this, on to Oarstone, and westward, to Talland, Pol- 

 perro, Lantioc bay, and the Fowey ferry at Bodinick, they 

 settle down to a high north and north-eastern dip. From Lan- 

 tioc bay their southern line or terms, quitting the coast, strike 

 off by Lanteglos and the Fowey ferry to " ancient inscribed 

 stone " on the Ordnance map, on the north-west of Fowey, 

 where they curve round and follow nearly the north and south 

 line of road to Lostwithiel for two miles and a half, from 

 whence they tread off obliquely to the north-east to Lantine, 

 on the west bank of the river, opposite St. Winnow, where, 

 meeting with their northern line, they taper out to nothing : 

 from Lantioc bay, after their south, and round their west 

 line just described, they are manifestly included in a trough 

 of the subordinate fossiliferous killas No. 3, which supports 

 them everywhere along its northern and north-eastern confines, 

 and is distinctly seen to emerge from below them at Lantioc 

 bay ; at a little south of Bodinick, and north of Fowey, and 

 all round their curved line up to Lantine. From Pencarrow 

 point and the Greber head round by Par sands and St. 

 Blazey, to the granite at Lanlivery, a powerful abnormal force 

 has wrenched the beds out of their mean direction into a huge 



Phil. Mag. S. 3. Vol. 24. No. 160. May 1844. Z 



