33 



variety of grauwacke, containing stems of encrinites, corals, and bivalve 

 shells. 



5. Trap Rocks. — The connection of these rocks with the disturbed 

 state of the stratified deposits, constitutes the chief interest of the 

 tract described in this paper. A small headland, east of Babbacombe, 

 consists of greenstone containing much iron pyrites, and traversed 

 by veins of quartz, jasper, &c. ; the contiguous limestones being 

 semi-crystalline. On the west of the same place, another headland 

 is composed of porphyritic greenstone, occasionally amygdaloidal : 

 — and here the trap is protruded upwards, into the overlying argilla- 

 ceous slate of the carboniferous limestone ; the adjacent beds of shale 

 being broken, much contorted, and some portions of them even in- 

 cluded in the mass of trap ; whilst the limestone in the upper part of 

 the cliff also is much dislocated. In the inaccessible cliffs near Oddi- 

 combe Sands, the trap has intruded itself among the limestone and 

 shale, the beds of which are much altered in character, and so broken 

 up near the summit, that they are with difficulty distinguished from 

 each other. The largest mass of trap on this part of the coast is at 

 Black Head ; and is remarkable as inclosing a large detached portion 

 of the contorted limestone. 



Near to a great fault at Oddicombe Sands, the argillaceous slate is 

 elevated to the top of the cliff, and the adjoining new red conglome- 

 rate also rises, as if forced up by the same movement which had 

 affected the slate. 



The author conceives that the appearances of the coast which he 

 has described, point out two distinct geological epochs : — 1st. That 

 of the formation of the new red conglomerate, after the limestone 

 and shale had been partially broken up. 2ndly. The intrusion of the 

 trap, at a period subsequent to the deposition of the conglomerate 

 and new red-sandstone. And besides attributing the disturbed state 

 of this region to the operation of trap, the author is disposed to refer 

 to the same period and agency, the great dislocations in the oolitic 

 series on the east of the tract which he has described ; and to con- 

 nect with the convulsion by which he supposes that disturbance to 

 have been produced, the greater catastrophe which elevated the 

 chalk of the Isle of Wight, — and even, possibly, that which threw up 

 the main ridge of the Alps. 



A paper was read, entitled, " Supplementary Remarks on the 

 Strata of the Oolitic series, and the Rocks associated with them, in 

 Sutherland, Ross, and the Hebrides ;" bv Roderick Impey Murchison, 

 Esq., Sec. G.S. F.R.S., &c. 



The author, in company with Professor Sedgwick, having visited, 

 during the last summer, the districts which he described in a former 

 memoir (Geol. Trans. 2nd series, vol. ii. part 2.), has been enabled to 

 make some additional observations, and to collect further specimens 

 illustrative of the strata of the oolitic series, and their associated rocks 

 in the north of Scotland. 



1. On the connexion of the primary rocks with the secondary 

 deposits, on the east coasts of Sutherland and Ross. — The Ord of 

 Caithness, and the mountainous ridge connected with it, which had 



