CRIFFEL DISTRICT. 147 



of formation. The felspar which enters into the composi- 

 tion of the granite and syenite varies in colour from white 

 to grey and light brick-red, while the quartz is invariably 

 of the usual grey colour ; the mica is in general brown, and 

 occurs only in minute scales. In several places, the granite 

 assumes a porphyritic aspect, the crystals which produce this 

 arrangement being invariably of felspar ; but on the large 

 scale there is no example of determinate structure, — that 

 tabular appearance which is so often to be observed in ex- 

 tensive granite districts never occurring here. The syenite 

 which is associated with the true granite is, like it, small gra- 

 nular, and from the hornblende varying in quantity, the 

 rock assumes various aspects. Sphene occurs in minute 

 crystals, and may be observed in the syenitic cliffs about 

 two miles to the north of New Abbey. Contempora- 

 neous veins occur in the granite and syenite, and appear 

 to have been produced during a state of the rock capable 

 of allowing the free motion of its constituent minerals ; some 

 of these veins are composed of quartz, while others consist 

 of a granite of a smaller grain than that which they traverse. 

 They run courses more or less tortuous, pass more or less 

 into the bounding walls, and when well exposed may be 

 found thinning completely out at both extremities. On 

 examining any considerable tract of this country, numerous 

 concretionary masses are to be observed in the syenite. 

 They vary from a small size to one or two feet, being either 

 of angular or ovoidal shapes, and in general are com- 

 posed principally of hornblende; frequently all the com 

 stituents of the syenite, however, enter into the composi- 

 tion of these masses, and sometimes they become porphy- 

 ritic by containing crystals of felspar. In regard to the 

 appearance of the concretions at the planes of contact 

 with the rock in which they occur, it may be remarked 



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