Mr. Winch on the Geology of the Banks of the Tweed. 15 



feet, and is situated more than twenty feet above the river. 

 The stone here has a slight tinge of red, similar to the stra- 

 tum in the upper part of the cliff at Firebourn, which abuts 

 against the calcareous beds. It dips to the southward, and is 

 divided by thin slaty micaceous partings, and capped by about 

 ten feet of loose sand, the abode of flights of sand-martins. 

 On the north side of the Tweed, at the distance of a mile 

 above Twizell Ferry, rocks of well-defined red sandstone make 

 their appearance. It is fine-grained in texture, of a dark red- 

 dish-brown colour, and abounds with spangles of silvery mica. 

 The cliff is of considerable elevation, and from hence to the 

 sea coast, thick beds of red and variegated sandstone, at some 

 places covered by the thin calcareous strata previously men- 

 tioned, and at others interstratified with them, become preva- 

 lent, though coal measures may be noticed in their vicinity. 

 On descending the river until opposite Twizell Boat- House, 

 fine-grained micaceous red sandstone rocks, and those of the 

 coal formation, or at least such as have heretofore been con- 

 sidered exclusively as such, are in close contact. On the 

 north shore, low rocks of the latter description appear in situ, 

 and it may be worth remarking, that, on ascending the river 

 Till, for the distance of a mile westward, Twizell Castle may 

 be seen, built on an extremely hard gray micaceous sandstone, 

 filled with coal scars*, and so promising did this neighbour- 

 hood appear, as to induce the proprietor to make a trial for 

 coal. Three-quarters of a mile further up the Till, the red 

 rocks are again met with, and worked at Mill Quarry, but at 

 Dunston Haugh, two miles and a half from the Castle, the 

 stratum quarried is yellowish-white, and seemed to be a coal 

 sandstone. But to return to Tweed side. On the south bank, 

 above the Ferry House there is a perpendicular cliff, forty 

 feet high, of white sandstones, though tinged red on their sur- 

 faces by the oxidation of their mica ; the beds are separated by 

 thin micaceous partings, and in every respect resemble the rock 

 quarried below Lennel. On the north side, just below the ferry, 

 the cliff is not less than 50 feet above the stream, and composed 

 of fine-grained red sandstone, with small scales of silvery mica. 

 On descending the river, the rocks on the south shore con- 

 tinue red, micaceous partings divide the thick strata, through 

 which nodules of red ochre are dispersed in abundance, and 

 those on the north side agree with them in every character. 



* Minute fragments of red garnets are embedded in this sandstone ; a 

 circumstance I have never noticed in the sandstones of the Newcastle coal- 

 field; but in the millstone grit at Shaftoe Crags, near Wallington, the same 

 mineral was detected by W. C. Trevelyan, Esq., and it abounds in the 

 grauwacke of Bournmouth, north of Berwick. The Twizell sandstone I 

 suspect to be an old member of the carboniferous limestone formation. 



Opposite 



