TOPOGRAPHY AND GEOLOGY 37 



Some 400 lakes are indicated on the map of this region. These 

 reservoirs have a total area of 103,000 acres — 7 per cent of the entire 

 area. 



Topography. — The country consists of innumerable low rounded 

 hnis and ridges. In the great majority of cases there is less than 100 

 feet difference in altitude between the streams and the ridges which 

 separate them. Often the divides between the smaller streams are 

 nearly flat or slightly rolling in character. When the higher ridges 

 are ascended one sees an even sky-line and the country has the appear- 

 ance of a flat plain into which countless depressions have been etched 

 by the streams. Scattered over the region are occasional hills and 

 ridges which stand from 200 to 300 feet above the general level of the 

 plain, as, for example, in Tudor township between Millbridge and 

 Glanmire, the Blue mountains in Methuen, the Green mountains in 

 Glamorgan, and the granite ridges in central Anstruther. Along the 

 northern limits of the watershed, the valleys are deeper and narrower, 

 and the general elevation of the plain or plateau is about 1,250 feet 

 above sea level. The northern portion of the watershed in Haliburton 

 coimty is approximately 500 feet higher than Stony lake, and the 

 southward slope of the plain is about 8 feet to the mile. The ridges, 

 for the most part, have a northeast-southwest direction, and practically 

 all the larger streams flow towards the southwest. 



Geology. — The rocks of the region consist of various kinds of 

 granite and gneiss, crystalline limestone, amphiboHte, gabbro, diorite, 

 syenite, and sedimentary limestone of Black River age. Except the 

 Trenton limestone, none of these occur in large areas in pure condition, 

 since both the granites and crystalline limestones are often mixed with 

 bands of gneiss and amphiboHte. The whole region was once covered with 

 sedimentary rock, mostly limestone, and in some crustal movement 

 of the earth the granite and other plutonic rocks were pushed up through 

 it. The forces concerned changed the limestone into its present 

 crystalline form and brought the amphibolites and gneisses into 

 existence. Three distinctive lines of these intrusive rocks cross the 

 area in a northeast-southwest direction, and, being harder than the sur- 

 rounding rock, they constitute the higher points in the topography. 

 The eastern line of intrusive rock is interrupted, but it can be traced 

 through the Blue mountains in Methuen, "The Ridge" in southern 

 Wollaston, and the rugged diorite ridges in the northeastern portion 

 of the towTiship. The middle line of eruptive rock extends northward 

 through portions of Burleigh, Harvey, and Anstruther in a soHd mass 

 of gneissic granite, and then, with some interruptions, joins the great 

 granitic outcrop to the north of the Trent watershed. The western 

 outcrop of eruptive rock, begins in Galway and extends through 



