104 GEOLOGY OF THE LOTHIANS. 



along with minute masses of quartz ; it is only visible in situ 

 in the bed of the stream, but as numerous blocks are strew- 

 ed over the surface of the adjacent hill, it is probable that 

 this vein is related to the strata, both as a dyke which runs 

 parallel to their direction, and also as an overlying mass. 

 Near this, a rock of felspar containing crystals of augite 

 appears, but there are no opportunities afforded for deter- 

 mining its relations. Felspar, both compact and porphy- 

 ritic, occurs in many of the hills in this quarter, but its 

 modes of connexion with the greywacke are in no instance 

 ascertainable. In the hills of Redstone Rig and Newland, 

 felspar rocks are met with, and at Kidlaw, a farm near the 

 House of Newton, there are exposed two dykes of felspar, 

 which traverse vertically the grey wacke slate; and on proceed- 

 ing up a stream, which runs from the hill of Middlemuir, 

 the same strata are associated with a vesicular felspar, which 

 is quarried and used for lining kilns, but nothing can be 

 discovered in regard to the modes of its connexion with the 

 strata. In the bed of a stream which runs past the farm of 

 Newlands, a compact felspar is associated with the transi- 

 tion slate, on which horizontal strata of red sandstone con- 

 glomerate rest, a circumstance of importance, as it renders 

 it highly probable that the eruption of the unstratified rocks 

 connected with the greywacke has been anterior to the depo- 

 sition of the secondary strata of this district. Near Fala, 

 in a ravine which leads down from the hill of Pockbie, se- 

 veral veins of porphyry occur, associated with the vertical 

 strata of greywacke. The basis of this porphyry is of a 

 yellowish-red compact felspar, and contains numerous acicu- 

 lar crystals of a light green hornblende ; its associations with 

 the strata are, however, in no instance interesting. 



Concerning the relations of the unstratified rocks of West 

 Lothian to the several strata with which they are connected, 



