Figs. 1 and 2 Rolls, at the Lake mine. 
These are minor crumplings or corrugations with variable axial strikes, due 
to cross-folding believed to have occurred during the intrusion of the 
Pochuck magma and induced by that intrusion. 
They are more prominent in the emerging parabola-shaped ends of pitching 
synclines. The larger synclinal structures (not rolls) and the associated anti- 
clines, are believed to be inherited from the previously folded and metamor- 
phosed Grenville strata. 
The rolls here shown were formerly covered with magnetite which out- 
cropped on the north slope of the hill. The ore was stripped from the sur- 
face when the Sterling and Lake mines were first discovered, and was sub- 
sequently followed under the lake in the present workings. 
150 
