THE METAMORPHIC ROCKS OF ADELIE LAND. STILLWELL. 



29 



calcite when the last three are not separately determined. Quartz is never abundant and 

 nearly always very subordinate ; as it is very difficult to distinguish it in all cases from 

 the clear secondary felspar, very little is lost in value and a great saving in time is effected 

 by reckoning it in with the felspar. Apatite, lawsonite, and calcite are separately 

 measured when sufficiently abundant, otherwise their presence is indicated by p. The 

 heading " iron ore " includes magnetite (or ilmenite) and pyrite as pyrite is very sporadic 

 and occasional. " Mica " includes biotite and chlorite, which are frequently intergrown. 



TABLE 1. 



1. A fine-grained micaceous type which has proved more resistant to weathering than the surrounding 

 granodiorite gneiss. 



2. The same rock as 1, but measured in a section parallel to the schistosity. 



3. An example that appears as a system of irregular schlieren rather than as a distinct band. 



4. A normal band which contained irregular quartz segregation veins carrying large epidote crystals. 

 The quartz in-filling is subsequent to the band and the foliation. 



5. A well-defined band from which No. 720 is the single specimen in the collection. 



6. An abnormal band containing one of the remarkable biotitic patches. The sample was collected 

 as the " normal " part of the band, a few feet away from biotite clot. 



7. A typical massive type taken from the band which contains the xenolith. 



8. Normal band. 



9. A sample of a schliere of dark rock in the granodiorite gneiss. The schliere is impregnated with 

 felspar-quartz veins which have participated in the folding and are contorted. 



10. Normal band. 



11. A band situated between No. 10 and No. 12. These three bands lie very close together and are 

 not separated by more than a yard from each other. 



12. Normal band. 



13. Massive amphibolite which is here inserted for comparison. It grades out in parts into felspathic 

 gneiss and in part into pure hornblendic rocks. 



The table indicates that we have three main varieties in this suite of rocks 



1. Rocks containing dominant biotite (e.g., No. 153, which will be described 



as an epidote biotite schist). 



2. Rocks containing biotite and hornblende in approximately equal proportions 



(e.g., Nos. 412, 630, the biotite amphibolites). 



3. Rocks containing dominant hornblende (e.g.. Nos. 629, 631, etc., the 



amphibolites). 



