382 T. W. E. DAVID, F. B. GUTHRIE, AND W. G. WOOLNOUGH. 



subject. For this portion of the paper we would specially express 

 our obligation to the works of F. von Zirkel and H. Rosenbusch. 

 We also desire to thank Mr. A. J. Peterson, B.Sc, and Mr. L. C. 

 Green for their kind assistance. Our thanks are also due to Mr. 

 E. F. Pittman, Assoc. R.S.M., the Government Geologist, for placing 

 the Geological Survey Library at our disposal. 



