ASSOCIATED METAIUORPHIC ROCKS OP THE LAKE-DISTRICT. 25 



division (green slate and porphyry) in an unusual state of crystal- 

 lization''" (see Appendix, p. 26). 



If the analysis just given be now considered, we shall see how 

 far this old view of Sedgwick's is rendered probable. Unfortunately 

 I have not at present analyses of the lavas of Eycott Hill, which 

 seem to be of a generally more basic character than the one chosen 

 as representative of the more southern contemporaneous traps. 

 However, if G and H be contrasted, the likeness in composition is 

 sufficiently evident ; and I doubt not that an analysis of the por- 

 phyritic dolcrite (contemporaneous) of Eycott Hill and the country 

 to the north would correspond still more closely with G. On the 

 other hand, if E be compared with E (p. 22), representing an ashy 

 and more highly silicated member of the volcanic series, consider- 

 able correspon deuce is again found to prevail. When these facts 

 are taken into account, together with those previously brought 

 forward, it seems, I think, in the highest degree probable that these 

 various masses represent neither truly intrusive rocks nor old centres 

 or foci of volcanic eruption, but rather a series of interbedded vol- 

 canic rocks of somewhat varying composition which have been me- 

 tamorphosed in situ, the result being masses of felsite, diorite, and 

 hypersthenite — the first the product of the |most highly silicated 

 beds, and the latter two of the less silicated and augitic lavas. If 

 this be the case, the names given above to these masses must be re- 

 garded as correct only in a limited sense, as suggesting that these 

 old volcanic beds have been so metamorphosed as to take on felsitic, 

 dioritic, or hypersthenitic characters, these characters being by no 

 means persistent and universal over large areas. Owing to the 

 depth at which the metamorphism took place, the rocks have pro- 

 bably been partly silicated from below ; and certainly much of the 

 quartz is of secondary formation. 



Summary. 



1. The quartz felsite of St. John's Yale and the syenitic granite 

 of Buttermere and Ennerdale lie, for the most part, at the junction 

 of the volcanic and Skidd aw series, and seem, by their line of strike 

 and by the occasional presence of bands of slate or volcanic rock 

 enclosed within or running through them, to represent the transition 

 beds between the two series metamorphosed in great measure in situ. 



2. Microscopic examination seems to prove the occasional passago 

 of certain parts of the Skiddaw Slate into quartz felsite (PI. II. 

 figs. 1 & 2). 



3. The chemical examination, so far as it goes, shows the pos- 

 sibility of these rocks being formed by metamorphism out of the 

 volcanic series and included beds of Skiddaw Slate. 



4. Evidence gathered in the field, and microscopic and chemical 

 examination, all seem to suggest that the rocks of Carrock Eell &c. 

 represent the base of the volcanic series, consisting largely of con- 

 temporaneous traps thrown into a synclinal the axis of which ranges 

 generally east and west, and metamorphosed into rocks of greatly 

 varying character. 



