12 J. CLIFTON "WARD ON THE GRANITIC, GRANITOID, AND 



II. Microscopical Examination. 



1. St.-John's Quartz Felsite and altered Skiddaw Slate. 



2. Crag-Bridge Quartz Felsite. 



3. Buttermere and Ennerdale Syenitic Granite, and altered Skiddaw 

 Slate. 



4. Carrock-Fell Eocks. 



a. Spherulitic Felsite. 



b. Diorite ? (altered dolerite). 



c. Hypersthenite (altered dolerite ?). 



III. Chemical Examination. 



1. Bocks of St. John's Vale and of Buttermere. 



2. Eocks of Carrock Fell. 



Summary. 



Appendix : Notices of papers on these rocks by other authors. 



Introduction. 



I now propose to describe the mode of occurrence of several masses 

 of quartz felsite, syenitic granite, and other rocks, together with 

 their metamorphic associates. Following the plan adopted in the 

 two previous Parts, the appearance of these rocks in the open country 

 will first be noticed, and be followed by the microscopical and 

 chemical examinations. Although the several masses are detached 

 from one another, it will, I think, be better to describe the rocks 

 together, in each section, as noted above, rather than to treat of each 

 mass separately in all its bearings. The same order of description 

 being preserved, however, in each section, it will be possible, when 

 desired, to take each rock separately under the various heads of 

 examination, and read all that relates to it independently of the 

 others. 



I. Examination in tJie Field. 



1. St.-John's Quartz Felsite and surrounding rocks. — This rock 

 occurs on either side of the lower end of the Yale of St. John, 

 forming two masses, each about one mile long from north to 

 south and a half to three quarters of a mile broad (Q.F. fig. 1). 

 It is usually of a pale colour, though sometimes assuming a red tint, 

 and consists mainly of quartz and felspar in a felsitic base. The 

 quartz is crystallized. The felspar is orthoclase and oligoclase, the 

 latter being much altered into a yellowish-green steatitic mineral. 

 Mica is sparingly developed; and a small quantity of hornblende 

 may perhaps occasionally be present. The rock not unfrequently 

 contains large fragments, much altered ; it is generally well jointed, 

 as at Skundraw, and in some places shows lines of what appear to 

 be former bedding. 



Its distribution and appearance in the mass is very striking, ex- 

 cept on the south. Each tract appears to be surrounded by Skiddaw 

 Slate, although, the ground being much drift-covered, the slate is 

 only seen at a few points, and at some of these shows little sign 

 of alteration. The western tract is, I believe, faulted on the 

 south against the volcanic rocks of High Bigg ; and when looked at 



