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



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 ex- 

 hibits 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 iden- 

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

 and positions unconformable. 



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 arranged in the following order: 1st, 

 fine-grained pale red sandstone ; 2nd, a thin stratum of slaty 

 micaceous sandstone ; 3rd, twenty-five feet of dark red mica- 

 ceous sandstone; 4th, shale, with thin strata of encrinal lime- 

 stone; 5th, red sandstone, divided by the same limstone : 

 the total thickness of these beds is one hundred and twenty 

 feet. Below Spital Mill, half a mile further south, a thick 

 stratum of sandstone, of peculiar appearance, crops out; it is 

 yellow, blotched with red, and is very friable, its grains scarcely 

 adhering; and on the beach, about twenty yards north of this 

 spot, the limestone is separated by a parting of ash-coloured 

 shale, containing bivalve shells (Corbula limosa, Fleming's 

 British Animals, 426.) in abundance. Near Spital Farm, a 

 dark gray compact limestone, containing vegetable exuviae, 

 similar to those noticed in the limestone in the dyke on the 

 north side of the harbour, rises to the day about high-water 

 mark, and may be considered another of the anomalous rocks 

 of this coast. At the foot of the rail-road, situated a little 

 further south, coal sandstone, inclosing casts of large vege- 

 tables, (Stigmaria Jicoides, Sternberg, t. 12. f. 1, 2, 3; and 

 Lepidodendron obovatum, t. 6. f. 1.) and bituminous shale al- 

 ternate, beyond which a quarry has been worked in the red 

 rock to the depth of forty feet. The stone it affords is hard 

 and fine-grained, and has been used in constructing the new 

 pier. Proceeding southward to Huds-head, the red rock, of 

 which the cliff here consists, abuts against the coal sandstone, 

 which is close behind it, and within two hundred yards one 

 of the Scremerstone shafts is sunk. At North Scremerstone, 

 two miles from Berwick Bridge, the rocks are red sandstone, 

 shale, and encrinal limestone, the latter of which has formerly 

 been quarried, and a little to the south, an extensive quarry 

 is now open at a place called the Red Houses. The stratum 

 is 18 feet thick, and affords a blueish-gray stone, close in its 

 texture, and containing encrinites. It dips at an angle of 

 4-5, and undulates in the same way as the limestone upon the 



beach 



