CONCLUSIONS 143 



ties are on\y 1,000 feet above the sea, though some terraces rise to 1,1.T). 

 The prospectors of tlie ref^ion, who have taken u}) ahnost tlie wliole 

 lengtli as placer claims, think the gravels belong to an old river much 

 larger than the Vermilion; but there is little except the general down- 

 ward slope of the gravel plains to support this view. The gravels do 

 not follow a single valley, but sometimes occup}' two parallel valleys, 

 with a total width of two or three miles, and sometimes cease altogether 

 for a short distance. All the way down there are occasional terraces 

 such as might be formed by wave action. 



The fiict that this stretch of 40 miles is everywhere auriferous, while 

 sand and gravel areas of a similar kind to the south and west contain 

 little or no gold, suggests a common source of the materials between 

 Meteor lake and lake Wahnapitae; but the gold is generally exceed- 

 ingh^ fine, the largest color seen by myself having a value of only four 

 cents, and the scales are much rounded and flattened, suggesting that 

 it may have been transported from a considerable distance, very likely 

 by glacial means. 



Conclusions 



From the examples cited in the foregoing paper it will be seen that 

 beach lines and terraces more or less well defined occur in Ontario at 

 all levels from one or two hundred to fifteen or sixteen hundred feet 

 above the sea, those of medium height being, as perhaps might be ex- 

 pected, more distinct and continuous than the lower and higher ones, 

 since the opportunities for impressing themselves on the topograph}'' 

 were greater. Through various circumstances, due probably to the rate 

 of retreat of the ice and of the differential elevation of the region, some 

 of the water-levels lasted much longer than others, good examples of 

 the more permanent ones being afforded by the Iroquois, Nipissing, 

 Algonquin, and Warren beaches. As a general rule, the higher beach 

 lines are older than the lower ones, though there may be exceptions to 

 this, as in the case of the Nipissing beach as compared with the Iroquois, 

 the latter, though the lower, being the older of the two. This general 

 succession in age from higher to lower may be accounted for largely b}'' 

 the theor}'' of ice-dams, since the last ice-sheet retreated on the whole 

 in a northeasterly direction, the various bodies of water following up its 

 front and leaving the successive beach lines each more greatly tilted 

 than the next one below, if we project their planes to the same vertical 

 line at the northeast of the region. The Nipissing beach, however, not 

 having been formed in an ice-dammed body of water, will to that extent 

 be an exception. 



