TRANSACTIONS OF THE SECTIONS. 635 



their regular stratified appearance. An example of the strati* 

 fied trap may be seen at Fassney Water, (a locality described 

 by Professor Playfair,) and on the north face of Soutra, about 

 200 yards east from the London road. In these places it has 

 all the appearance of sienite, both from its hardness and the 

 intermixture of red felspar and hornblende. It is hardly neces- 

 sary to add that these sienitic and otlier trap strata, which ap- 

 pear in this stratified form, have acquired that condition from 

 the grauwacke strata, between which they have been pushed up 

 in a manner similar to what occurs in Salisbury Crags ; and the 

 like effect as is there seen has been produced upon the grau- 

 wacke rocks, which are greatly hardened, and even made to as- 

 sume so crystaUine an appearance as to render it difficult to find 

 the exact line of division. 



^ 2. The trap of St. Abb's Head belongs to a more recent pe-^ 

 riod. It may be traced, except for a very short hiterval, occu- 

 pied by grauwacke, southwards along the coast, to a point where 

 it is found enveloping the conglomerate of the old red sand- 

 stone. On this part of the coast the conglomerate may be seen 

 in vertical beds, and at another point, viz. at Eyemouth Har- 

 bour, in immense horizontal masses, resting on the trap, and 

 dipping, at a small angle, into the sea. Here copper is found 

 in the trap in great abundance, not in the form of veins, but 

 in small nodules, which, by oxidizing on exposure to the air 

 give a curious appearance to the surface of the rock, which is 

 in consequence speckled over with green patches. 



To the same epoch may be referred the eruption of most of 

 the trap-hills of Berwickshire ; those at least which have pro- 

 truded through the old red sandstones, some of which, as, for 

 example, the Eildon Hills, are about 1300 feet above the level 

 of the sea. 



There are trap-dykes which traverse the red clay beds and 

 sandstones of this formation, some of which run from Home 

 Castle, and in which numerous red crystals occur. Some of 

 these crystals are of that red colour and jasper appearance as 

 to lead to the opinion that the trap had occasionally taken up 

 some particles of the adjacent red strata and jaspidified them. 

 These dykes abound also with large crystals of glassy green 

 felspar. 



This old red sandstone trap is of various textures, from the 

 crystalline basalt to the friable and almost vesicular tufa which 

 is seen on the outskirts of the trap-hills. It sometimes also 

 occurs as a soft breccia or conglomerate, the imbedded portions 

 being manifestly derived from the rocks or soil among which it 

 had flowed. In one locality the conglomerate consists of very 



