84 



ME. C. E. TILLET ON THE GEA^'ITE- GNEISSES [vol. Ixxvil^ 



The pyroxene-bearing types behave similarly, and in the field it 

 is impossible to differentiate them satisfactorih\ The field name 

 ' amphibolite ' is utilized to include these types. 



Fig. 4. — Disrupted hands of cnivjiliiboliie in tlie granite-gneiss of 

 Sleaford Bay, ivith development of coarse j)egmatite heticeen 

 the separated fragments. 



am 



n I I I I I I ! M I 1 I I I r ni aqv 



g^n 



'U-LLU-LLTTT 



t-T^r-rVl i i( I 1 l± E3ii±i±iriqv 



•..gn 



hp -^\^ 



8' 



[gn =: gneiss ; am = amp]iibolite ; hp = hornblende-pegmatite ; 

 qy — qiiartz-Tein. J 



Enough, lias now been said to show that these dark bands 

 represent masses of anterior origin, whicli have been engulfed and 

 oriented within the flowing gneiss. The petrography and origin 

 of these rocks will be dealt with on a later page. 



Y. The Peteogeaphy of the Gteanites and Geanite- 

 Gtneisses of the Fjlindees Seeies. 



The granites and granite-gneisses of the Flinders Series are 

 coarse-grained rocks in which the dominant ferromagnesian con- 

 stituents are hornblende or biotite, or both. Although pyroxene 

 is certainly a constituent of some of the gneissic types, it is more 

 abundant in the massive varieties. In hand-specimens the rock 



