68 DR. A. E. DWEEEI HOUSE ON INTENSIVE EOCKS [Feb. I909, 



Ferromagnesian minerals are represented by a very small quantity 

 of greenish biotite, quite unlike the variety which occurs in the 

 altered andesite. 



The junction is everywhere sharp, and there is no sign of 

 absorption of the andesite having taken place. One of the felspar- 

 phenocrysts in this specimen is cut clean across by the contact-line. 



Fig. 4. — Hand-specimen of junction-breccia, from neat 

 iStonj/ 'Tarn. (See also pi- 67.) 





s^w^^ 





mL. $|jfoJBr v v, i^i* 



S£**£"V — '' W&xA 



1jtji 



^BfBJHPSjWit'* ' *^JH 



l&^jiWl «$^ fir"^ 



HC*- <~ j^MJij^H 





Hk^ JSpS 



Ft ^r Li " " ■! 



H I'iIhw^ ^B 







F^*bI 





W&* b&Aj 









An examination of fig. 4 will show that the andesite-fragments 

 in the breccia are extremely angular, in some instances possessing 

 knife-like edges. 



Many larger granite-veins penetrate the Borrowdale rocks, 

 in the same area, and consist of a pink, fine-grained, very acid 

 granite, in which quart/ and felspars are the principal constituents. 

 Specimen 132, from one of these larger veins, shows the usual 

 quartz-mosaic with larger crystals of perthite, quartz, oligoclase, and 

 also phenocrysts of micropegmatite. There are narrow secondary 

 veins of a mixture of epidote and quartz, running in various direc- 

 tions across many of these granite-veins. 



Specimen 108 was taken from the quartz-vein which occurs at 

 the junction of the granite with the Borrowdale rocks, one-third 

 of a mile north of Taw House in Upper Eskdale, and already 



