GRANITIC MASSES ENCLOSED IX GNEISS. 



373 



and sizes, of mica schist are seen in the gneiss where the gneiss predominates, and of 

 gneiss in the schist where the schist is the main rock.' * 



In some instances a mass of syenite inclosed in schist holds in itself 

 fragments of schist, as in fig. 5. In many cases also the schistic beds wrap 



Figure 5. — Schist inclosing Granulite, itself embodying .1/"-" schist, Burntside I 



around the gneissic fragmeuts, indicating that the fragments were introduced 

 while the schist was in course of formation ; and indicating, too, that the 

 gneiss had been already consolidated when the schist was forming (see fig. 

 tip. In very many (if these cases the gneissoid fragment has been bent in 





Figure S. -Bydromiea Schist wrapped around Masses of Granite, Farm Lake, Minn. 



a marked degree and shaped to the enwrapping schist. This seems to show 

 that the consolidated gneiss had been rendered plastic again. 



Sometimes the schists appear intertwisted without the presence of gneissic 

 fragments.^ Sometimes the included fragments are quartzitic, and the 

 mutual actions are the same.§ These phenomena indicate some relative 



* H. V. Winchell, Sixteenth Mian. Rep., p. 428. 



t-See further illustrations, fig. 36, Fifteenth Ann. Rep. Minn., p. 89 ; Ibid., fig. 38, p. 97. 

 This ia illustrated in figs. 4u and 42, Fifteenth Ann. Report Minn., pp. ill and 116. 



\ Si,,/,, nth Minnesota Report, p. 409. 



XLIX— Bin,. Gf.oi. Soc. A.m., Vol. 1, 1889. 



