Vol. 50.] OF CARROCK FELL. 337 



highly interesting district of Carrock Fell as a subject of study. He 

 bore testimony to the careful investigation of the area by the late 

 Clifton Ward. The Author's observations seemed to show that 

 concentration by crystallizing processes might go on in a mass 

 of large dimensions, as well as in dykes like those described by 

 Lawson and Vogt. 



Prof. Cole expressed the regret which all must feel that Prof. 

 Sollas could not be present to join in the discussion. The parallelism 

 of the so-called granophyre and the several layers of the basic rocks 

 seemed to suggest that the whole Carrock Fell mass might be a huge 

 composite dyke, the acid rock having intruded into the gabbro 

 distinctly on the north, and farther south as a plexus of minute 

 interpenetrations along the central line of the gabbro, giving rise 

 there to the gabbro with micropegmatitic groundmass. The micro- 

 scopic sections seemed to him to support this view, by reason of the 

 contrast between the basic areas and the patches of micropegmatite. 

 The aggregation of iron ores on the margins of the gabbro must, 

 however, be explained by some such theory as that which the Author 

 had put forward. 



Mr. Pxjtley considered that one of the most interesting points in 

 this valuable paper was the occurrence of lavas of the Eycott series 

 in the gabbro. How portions of lava-flows should become embedded 

 in a plutonic rock was a problem which seemed to need further 

 elucidation. The question whether the more acid character of the 

 central portion of the gabbro was due to differentiation of the 

 •original magma, or to incorporation, by fusion, of apophyses from 

 the adjacent granitic rock, was an open one; but it seemed probable 

 that, if the latter hypothesis were the true one, the alteration, where 

 the gabbro was seen to come into contact with the granitic rock, 

 should extend over a wider area than that represented in the 

 section. 



The Author thanked those who had spoken for their remarks. 

 In reply to Prof. Cole, he said that, while believing in a probable 

 genetic relationship between the granophyre and the gabbro, he 

 did not think that the injection-theory of Prof. Sollas afforded any 

 explanation of the regular distribution of the more or less acid 

 varieties of the gabbro. 



Replying to Mr, Putley, he described the occurrence of the masses 

 of Eycott lavas enclosed in and intricately veined by the gabbro, 

 but always with a sharply defined junction. All the phenomena 

 negatived the hypothesis of a metamorphic origin for the latter 

 rock. 



