30 JOURNAL OF THE 



evidence of their intrusive character. The form pre- 

 sented by the lamination planes of the g-neiss is that 

 of an eroded dome-shaped anticline, somewhat elon- 

 gated in almost a north and south direction. Even 

 after considerable observation in the field, it was my 

 impression that the peridotites of this area represented 

 a continuous sheet conformable with the lamination of 

 the g-neiss. But close, detailed mapping brought out 

 not only the enclosed body of gneiss mentioned above, 

 but also the irregular, protuberant apophysis at Ad- 

 die, and other projecting- arms at the crossing- of Scott's 

 creek, three miles west of Addie, and two in the vicin- 

 ity of Webster. Furthermore, there are ^ve distinct 

 breaks in the continuity of the eastern side on Cane creek, 

 and the isolated portions have the typical lenticular form 

 found in the majority of the outcrops. In the vicinity 

 of these breaks there is a narrow strip passing- off the 

 border of the map in a northeast direction, which is 

 also completely disconnected from the principal masses 

 of this reg-ion. 



This Webster rock shows the higfhest development 

 of lamination found in the whole belt, and the micro- 

 scope shows that the laminated rock is composed of 

 thin layers of finely granulated olivine alternating' with 

 coarser typical dunite. This condition, taken in con- 

 nection with the g-reat development of schistose talc in 

 the narrower portions, g-ives evidence of considerable 

 shearing-, which is most naturally ascribed to the move- 

 ments that gave rise to the anticlinal structure. The 

 other characters pointed out are explicable only as the 

 results of igneous intrusion. 



Much larg-er areas of g-neiss than those enclosed at 

 Webster are almost surrounded in the Buck creek area 

 by the peridotites and the later dikes of amphibolite. 



