124 Mr. Winch on the Geology of the Banks of the Tweed. 



slaty micaceous Sandstone, of an ash-grey colour ; 4th, Red Sandstone, 

 5th, Encrinal Limestone ; 6th, white Sandstone, blotched by Red 

 Ochre and containing Coal pipes ; 7th, Encrinal Limestone ; 8th, slaty 

 micaceous Sandstone j 9th, Encrinal Limestone ; 10th, Variegated 

 Sandstone. These strata occupy the space from the Sally-port to the 

 Pier. The Limestones are of inconsiderable thickness, and envelope 

 bivalve shells as well as encrinites. The Red and Variegated Sandstones 

 are very fine-grained, with but little Mica, and the Coal Sandstones 

 white, when not tinged by Yellow Ochre. At this point, which may be 

 about a hundred yards north of the Her, a slip dyke, of considerable 

 magnitude, intersects the cliff, and may be traced eastward into the sea ; 

 its breadth is three yards, the south side of the chasm being filled for 

 two yards by Shale, and the north side by a rib of brownish-purple 

 Limestone, so hard as to give fire with steel ; it is of a fine texture, with 

 a spUntery fracture, and impressions of the lanceolate leaves of some 

 species of Variolaria, of A. Brongniart, Stigmaria, of Sternberg, are 

 dispersed through it. The hade of the dyke is inconsiderable, but to the 

 south of it the strata dip to the south-east at an angle of 45°. A little to 

 the north the rocks become less inclined, and dip to the east at a trifling 

 angle ; the upper is a stratum of ash-coloured Shale, twelve feet thick, 

 filled with Producti — (Productus scoticus, Sowerby, Mineral Conch., t. 

 59, f. 3 ; and Productus antiquatus, t. 317j £ 1» 5, 6.) — the shells of 

 which retain their pearly lustre ; the lower stratum is Encrinal Lime- 

 stone, enclosing specimens of very large Producti — C Productus gigan- 

 teus, Sowerby's Mineral Conch., t. 320.) — being the same Fossil which 

 gives the name of Cockle-shell Limestone to one of the beds in the 

 neighbourhood of Alston. On the beach the Limestone is laid bare by 

 the action of the waves, and exhibits the extraordinary undulations long 

 since noticed in the stratification at Holy Island. Probably the stratum 

 may be the same ; but it is not safe to hazard conjectures on the identity 

 of mineral beds on a coast where their dips are so various, and positions 

 un conformabl e . 



On the south side of the harbour, at the distance of half a mile from the 

 bridge, the strata incline to the south-east at an angle of 45°, and are 



