Vol. 50.] OF CAEEOCK FELL. 313 



If the line between the main masses of gahbro and granophyre be 

 prolonged westward past Round Knott, it divides the gabbro which 

 ranges west of Iron Cratrs from the rock of Miton Hill, etc., Ward's 

 dubious ' diorite.' To this title the rock has no claim, containing no 

 hornblende except some of secondary formation, and it will here 

 be named ' diabase.' For reasons which will appear in the follow- 

 ing pages, I concur in regarding this as belonging to a separate 

 intrusion, distinct from the gabbro to the south ; but such a separa- 

 tion could not confidently be made on lithological grounds alone. 

 In both rocks the texture is very variable. The rock on Miton 

 Hill itself often assumes the coarsely crystalline characteristic of 

 a gabbro, while many specimens from the crags in the gabbro-area 

 would, if taken apart, be designated ' diabase.' The names will be 

 employed, with this explanation, to emphasize the distinctness of 

 the two intrusions and to mark their dominant characters. The 

 diabase is cut off to the north by a fault seen in the southerly branch 

 of Drygill, but it probably extends eastward under the much- 

 obscured ground north of Carrock Fell. 



In addition to the above rocks, I hope to notice in a future com- 

 munication a very interesting one which is seen at the junction of 

 Brandy Gill with Grainsgill and in the adjacent hillsides. It is 

 only incidentally mentioned by Ward as " a very quartzo-micaceous 

 granite." It is, indeed, a ' greisen,' 1 and is so named on the 

 Geological Survey map, where its boundary is indicated. This rock 

 is, as will be shown, connected with the Skiddaw granite, and has 

 probably no relation with the Carrock Fell intrusions. 



Excluding the rock last mentioned, and taking the others as a 

 whole, they are intruded, as is shown on the Survey map, among 

 that part of the great Ordovician volcanic series which is conve- 

 niently known as the Eycott Hill group, a group consisting essen- 

 tially of a succession of basic lavas. These lavas can be followed 

 along a curved and broken line of strike from Eycott Hill to Carrock 

 Fell, and they possess unique characteristics which place their 

 identity beyond doubt. No junction of the intrusive rocks and 

 these lavas is exposed along the northern line of boundary, although 

 the Eycott rocks are seen at Glints Gill, etc., penetrated by small 

 dykes and veins of granophyre. Along the southern boundary the 

 gabbro is faulted against Skiddaw Slates. Mr. Ward states that 

 the latter are " much altered," an expression which seems stronger 

 than the appearances warrant. A certain degree of alteration may 

 be granted, but it is doubtful how far this is connected with the 

 gabbro. Tracing the Skiddaw Slates up the Caldew valley towards 

 the granite and greisen, we find mere induration giving place to 

 'spotted' rocks, and these in turn to highly metamorphosed types 

 (' mica-schists ') to which Ward's description " much altered " well 

 applies ; but near Mosedale, where the effect of the gabbro can be 

 tested apart from the disturbing element of the granitic intrusions, 

 the alteration of the slate is not great. As regards the effect of the 



This rock was briefly noticed by me in ' The Naturalist' for 1889, p. 209. 



