THE seAP GRANITE AND ASSOCIATED KOCKS. 327 



Fig. 4 [87'3]. Liine-aiigite-roek in the metamorphosed Upper Coniston Lime- 

 stoue at the same locality ; showing coloiirlc'ss aiigite, both in crystal- 

 line aggregates with good cleavage and in granules and granular 

 patches. 8ee pp. .'}14-3ir). 



Fig. 5 [1218]. Si)ottcd schist in the metamorphosed Brathay Flags, north of 

 Wasdale Beck, about 3oU yards from the granite ; showing little spots 

 comparatively free from the secondary brown mica. This figure is 

 juagnified UK) diameters. See p. 319. 



Fig. (> [1223J. Quartzite, with colourless lime-augite, in the metamorphosed 

 Lower Coldwell beds (grits) just north of Packhouse Hill, about 580 

 yards from the granite. The pyroxene occurs in distinct rounded 

 granules and in finely granular patches. See p. 321. 



Discussion. 



Prof. BoNNEYsaid that it was almost impossible to discuss a paper of 

 such wide bearings, but it appeared to him to be one of great value. 

 The most important points were the clear demonstration of the 

 occurrence of felspar as a product of contact-metamorphism, and the 

 effects of the intrusion of an igneous mass on pyroclastic rocks. He 

 mentioned some cases which illustrated the uncertainty as to what 

 mineral might be produced by contact-metamorphism. 



Prof. Le jSTeve Foster said that the point which struck him as a 

 miner, with reference to the intrusive boss of granite, was the 

 absence of tin-ore. The Authors had remarked that no axinite or 

 fluorspar had been found, and that tourmaline was very rare. It 

 was interesting to note that where there was a lack of minerals 

 containing boron and fluorine there was a complete absence of 

 cassiterite. 



Mr. Strahan asked for an explanation of the connexion referred 

 to between the intrusion of the granite and the Pennine movements, 

 by which were usually meant post-Carboniferous movements. The 

 map exhibited of a necessity showed the dykes in a diagrammatic 

 form. He enquired if this radial arrangement with reference to 

 the granite would appear if they were shown on a true scale. In 

 the Cautley neighbourhood micro-granites of the same age as the 

 Shap granite occurred as sills in Coniston Limestone, and were cut 

 across by mica-trap dykes, which seemed to show that the more 

 basic rock was later than the more acid, and not earlier as argued 

 from inclusions in the Shap granite. 



Mr. Rutley thought that the red felstone-like dykes (often more 

 or less micaceous) were probably apophyses of the Shap granite, as 

 indicated by the Authors. With regard to the dark micaceous 

 dykes being in any way related to the highly micaceous inclusions 

 met with in the granite, he felt considerable doubt. Judging from 

 the alterations produced artificially in rhyolitic rocks by heat, he was 

 inclined to believe that the temperature under which the alterations 

 in the rhyolites had been effected in the Shap area was a compara- 

 tively low one. The occurrence of the peculiar polysynthetic 

 structure in the garnets which the Authors described was, he 

 believed, the first notice of such a structure in British garnets, 

 since, hitherto, it had only been observed in ouwarowite and in the 



