CAIRN MUIR-CARLOPS. 85 



dent for their upraisure, and the existence of these or si- 

 milar rocks, below the sandstone, fiiay easily have pro- 

 duced the disturbances which the position of the various 

 slates and sandstones evinces they must have been subjected 

 to. The sandstone-conglomerate which occurs in the bed 

 of the Linton Water is, near the farm of Cairn Muir, tra- 

 versed by a large vein of greenstone, which is in some 

 places amygdaloidal ; it cannot be traced throughout its 

 whole extent, but it runs a course parallel with the direction 

 of the strata, and gradually thins out. The conglomerate, 

 at its planes of junction with the greenstone, however, exhi- 

 bits no appearance of induration. (Plate X. Fig. 2.) 



The only other trap-rock which occurs in the Pentlands, 

 and deserves to be noticed, is a greenstone associated with 

 the red sandstone of Carlops. This mass of trap forms the 

 central part of a valley running E. and W. for nearly a 

 mile ; its sides are composed of red sandstone and con- 

 glomerate, having a position which, though not very sa- 

 tisfactorily displayed, appears to indicate that the strata 

 have been tilted up anticlinally. The trap which appears 

 to have been the agent in causing this arrangement does 

 not form an uninterrupted ridge, but, on the contrary, 

 has been broken up by subsequent actions, which have left 

 only portions expressive of its former complete continuity. 

 At the eastern extremity of this dyke of trap, the cutting 

 of a new road has exposed a vein of earthy greenstone, 

 which runs parallel with the strata of the white sandstone 

 series, and can only be considered as a lateral expansion of 

 the principal trap vein. The strata when in contact with 

 it are not altered, and both rocks dip S. S.W. at about 

 35°. At the village of Carlops, the eastern extremity of 

 this great trap-dyke is traversed by an infinity of veins 

 composed of quartz, in the different states of hornstone. 



