38 MR ste\t;nson on the geology of cockburnlaw, 



3. The Goal Measures. 



This important formation is represented in this district, by a small patcli 

 east of the CJumledge trap-dyke. Its strata are well exposed in the bed of the 

 Whiteaddcr, near Preston bridge, about a quarter of a mile below which, are two 

 fine sections. There the sandstones, shales and clays, which characterize the for- 

 mation, are seen dipping away from the dyke at high angles, and presenting the 

 usual appearances by Avhich this series of strata is elsewhere distinguished. The 

 shales and clays contain a large proportion of carbonate of lime in their composi- 

 tion ; so much, indeed, that they might almost be termed limestones. The sand- 

 stones ai-e of the usual white or yellowish colour, in many places highly micaceous, 

 and abounding in impressions of Stigmariae, Sigillarise, Lepidodendra, and other 

 plants of the carboniferous system. There is no appearance of animal remains.* 

 No coal seams appear, but there is a thin stratum of ironstone in nodules, which 

 abounds in remains of plants. The geological position of these strata, and the 

 other rocks of the same formation, which prevail in the Merse of Berwickshire is 

 consideraldy below the Encrinal limestone, which crops out near Berwick, and on 

 the sea-shore at Lamberton. Indeed, they properly belong to the mountain lime- 

 stone series, being situated far below the true coal measures. From their very 

 low position in the series, there is no reason to suspect the existence among the 

 Berwickshire strata of any coal-seams sufficiently thick to be worth working. 



II. Igneous Rocks of the District, and their Effects upon the Sedimentary 



Rocks. 



Throughout the district under consideration, trap-rocks are very abundantly 

 distributed, and present a field of speculation, no less attractive than those of 

 aqueous origin. The traps of the Lammermuirs and adjoining districts belong to 

 two great classes, differing from each other, as well in mineral character and 

 general aspect, as in regard to the epochs of their eruption. These are the For- 

 phi/ries and Greeintones, or Felqmtliic and Augitic traps, both of which classes are 

 very abundant, but (with one or two exceptions, to which we shall afterwards 

 have occasion more particularly to refer) do not occur associated with each other; 

 for it is a remarkable fact, that while the traps which occur among the groywacke 

 of the hills are uniformly of the Felspathic class, those which appear in connection 



• Within the last few weeks the remains of fossil fishes have been discovered in the course of 

 Langton Burn, about a mile SW. from Dunse, in strata belonging to the lower part of the coal mea- 

 sures. These remains consist of scales, spines, teeth, and other bones, similar to those found at Burdie- 

 bouse. They occur in a soft friable sandstone, which abounds also in Lepidodendra, and other plants 

 of the coal formation. Some remains of the Hohptt/chiiis have likewise been recently found in the old 

 red sandstone strata on the estate of Billie, about four miles NE. from Dunse 21st April 1845. 



