Evans and Bancroft — Gedrite in Canada. 509 



Art. LIII. — On the Occurrence of Gedrite in Canada ; by 

 N. Norton Evans and J. Austen Bancroft. 



In the year 1836 Thomson* reported the discovery of antho- 

 phyllite at Perth, Ontario, but although the authors have not 

 been able to gain access to Thomson's original paper, both 

 Hintze and Rammelsberg refer to the occurrence of antho- 

 phyllite at this locality as doubtful. Furthermore, the mineral 

 is not mentioned in the " Annotated List of Minerals Occur- 

 ring in Canada " compiled by G. C. Hoffmann. f It seems, 

 therefore, very doubtful whether the mineral has hitherto 

 been found in Canada. So far as can be ascertained further- 

 more, the mineral has never been found in place in the United 

 States, although it was found in bowlders of dunite at Bakers- 

 ville, North Carolina, by the late Professor S. L. Penfield. 

 The aluminous variety of this species known as gedrite has, 

 however, been recently found by Dr. Frank D. Adams occur- 

 ring abundantly in amphibolite on Lot 11 of .Range IX of the 

 Township of Harcourt, Haliburton County, Ontario. The 

 discovery was made in the course of the geological survey of 

 a large area on the margin of the Laurentian Protaxis to the 

 north of Lake Ontario, which has recently been completed 

 by Adams and Barlow for the Geological Survey of Canada. 



The occurrence of amphibolite in question belongs to the 

 Grenville series, which is very extensively exposed and is of 

 great thickness in this region, consisting chiefly of limestone 

 with, however, a considerable amount of associated amphibo- 

 lite. Towards the southern margin of the Protaxis the Gren- 

 ville series has an almost continuous development, but on going 

 north it is invaded by great bathyliths of gneissic granite 

 which rise through it and induce in it extreme metamorphism. 

 Still farther north the granite appears in increasing abundance, 

 the Grenville series being represented by long curved belts 

 and irregular patches distributed through the invading rock. 

 One of these belts, consisting of impure limestone, crosses the 

 north end of Elephant Lake in the Township of Harcourt, 

 being about seven miles in length and half a mile wide,- and 

 completely surrounded by the granite referred to above, whose 

 foliation coincides with the direction of the strike of the lime- 

 stone. 



About a mile and a half from the northern extremity of this 

 limestone belt, in the direct line of the strike and of the folia- 

 tion of the enclosing granite, there appears a narrow belt of 



* Records Gen Sc. Edinb., iii, 336, 1836. 



f Ann. Kept. Geological Survey of Canada, 1888-89, pp. 1-67 T. 



Am. Jour. Sci. — Fourth Series, Vol,. XXV, No. 150. — June, 190S. 

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