GRENVILLE SERIES OF EASTERN NORTH AMERICA 629 



FEET 



Limestone of Jack's Lake 6,770 



Rusty weathering gneiss with associated amphiboUtes, crossing Lots 



29-35 of Range I of Anstruther 5)754 



Limestone with bands of sedimentary ("feather") amphibolite north of 



Loon Lake 3>o6o 



AmphiboHte north of Loon Lake 2,190 



Limestone at Duck Lake (nearly flat, only surface exposed), say 50 



17,824 



Another line of section along which the Grenville series is excel- 

 lently exposed and along which measurements with a view to deter- 

 mining the thickness of the series may be made, is furnished by the 

 Hastings road. This is one of the most striking sections of strata 

 of pre-Cambrian Age to be found anywhere in the world. The road 

 was constructed many years ago by the government for the purpose 

 of enabling settlers to penetrate into what was then a very wild, remote, 

 and inaccessible portion of the Dominion. A line was drawn on a 

 map and orders were given to lay out the road along the line in 

 question. The result was that a long road was constructed, starting 

 from the rear line of the township of Madoc, running in an almost 

 straight line to the Madawaska River, holding throughout almost its 

 entire course a direction of N. 20° W. This road, which traverses 

 the whole width of the Bancroft sheet and almost the whole width of 

 the area embraced by the Haliburton sheet, fortunately for students 

 of geology, runs about at right angles to the strike of the country 

 rock, and throughout the whole southern portion of its course traverses 

 the Grenville series, affording excellent exposures. The selection of 

 this course for the road was, however, correspondingly unfortunate 

 for the settlers who took up land in the district, since the road holds 

 its course quite irrespective of hill or valley, and in its course passes 

 directly across several great gabbro intrusions which give rise to an 

 exceedingly rough type of country, and which might easily have been 

 avoided had a shghtly different line been adopted. 



As will be seen by consulting the Bancroft sheet of the Ontario 

 series of maps now being issued by the Geological Survey of Canada, 

 throughout a distance of 25.3 miles from lot 30 of the township of 

 Madoc to 60 in the township of Faraday, except where it crosses 

 the gabbro intrusions above mentioned, whose width has been 



