• >. 



8 



A. WINCHELL — RESULTS OF A.RCHEAN STUDIES. 



area, therefore, is essentially dome-shaped, and the crystalline and semi- 

 crystalline schists appear to have once extended over the dome and to have 

 been subsequently denuded fig. 7 i. In some cases the proximate vertically 

 of tin' structure persists i<> tin- middle of the granitoid ana ami quite across 

 ii. We must, nevertheless, conceive the middle of the area as tin' position 

 of an anticlinal axis or point. 



... o 



w 3 



a o 



O 



u: 



< 



5 £ 



2 



^ o 



V 



■ 2 



: o 



u 



u 



z- 



IS 

 t.. 



z 

 O * 



o 



z </> 



a. \ 

 O . 



• ' ••• ■ • 





Fioueb 7. — Plan of the Folding of the Orystalline and Semi-Cfrystalliru Roeki ■ "■ Wo thv 



■casionally the single synclinal becomes two or perhaps three with partial anticlinal* inter- 

 calate'!. 



It will be inferred from the structure described that a traverse from side 

 t i Bide of the semi-crystalline zone exposes the members of the series in di- 

 rect and then in inverted order and gives twice its total thickness. Simi- 

 larly a traverse across the area of crystalline schist- and gneisses presents 

 the succession in direct and inverted order and gives twice the exposed thick- 

 of those terranes. 



The Lithologk \i. ( Ionstiti riOM of the System of Semi-( Irystalline 



Schists. 



The lithology of this system is obscure, anomalous, multifarious, and w ith- 

 • >ui parallel in any other part of the earth's crust. It is essentially a system 

 of bedded rocks, bul they are cul by numerous basic eruptives. The beds 

 are mostly clastic, bul in place- they present the aspect of decayed diabasic 

 sheets. Certain beds unequivocally fragmental in one locality pass along 



nnii of theae Bchl • l In my Report of observations for 1886 



i ii' l also by Dr. Lawaon Id tils Report on the Lake of the w I* 



in iK8tj iji. \"~. Bin he ••••in- to detect evidences, In some Quaes, "i two or three synclinal* in the 

 width ••! tli" belt. I his 



• >f i • iti ucture 



- may • io without any ohange in oar conception "f the mechanics 



