360 GEOLOGICAL APPEARANCES 



stratified, nor in beds. Sometimes it presents an appearance 

 of veins, a few inches in breadth, and consisting of a brown- 

 ish-red compact felspar, hornblende in large distinct grains, 

 with a curved foliated fracture, and a little quartz. These 

 veins, if they deserve that name, differ from those of the red 

 sienite already described, in the irregularity of their outlines, 

 and in a slow gradation on their sides into the contiguous mass-. 

 In the bed of the Tilt, not far from where it receives the 

 Crochie, there is a rock of a similar character as to its consti- 

 tuents, which is in some places cut by veins of the red sienite, 

 and the lines of junction are there precisely marked. 



136. On the east side of the foot of the fall of the Crochie, 

 and nearly on a level with the grey sienite, or sienitic greenstone 

 on the opposite bank, (par. 29.) the rock is of a character similar 

 to that last described, though its structure approaches to slaty. 

 It effervesces slightly with muriatic acid, and seems to be a 

 compact dolomite, penetrated by talc and chlorite. It is pro- 

 bable that a great part of the base of the mountain, between the 

 Crochie and the head of the Glen, consists of similar a<r«:re- 

 gates ; for a cut made by a brook farther up, shewed the rocks, 

 to the height of two or three hundred feet, to have a strong re- 

 semblance to those that form the channel of the Tilt *. I 

 consider all these congenerous rocks as belonging to the pri- 

 mary strata. In their constituents they resemble some of the 

 compounds that I enumerated in the general sketch of the stra- 

 ta through the valley ; and one of them, which has been men- 

 tioned as occurring in the bed of the Tilt, not far from the 



junction 



* Some of these substances bear a considerable resemblance to those which, 

 appear on the Malvern Hills, in the cut made by the road to Ledbury. The 

 latter are in a state of decomposition, which makes it difficult to discern their in- 

 gredients. 



