HISTORICAL NOTICKS. 13 



jiiul inetL'oroloo'k'iil olijeclioiis iniu'lit l>i' ui'^xmI a,Li;aiiist it, 

 aiul tliiit it was not in accordance with the facts which I 

 had myself observed in Xova Scotia and in Cana(hi. 'J'he 

 additional facts conlaincd in the ])resent report enable 

 me to assert with confidence, thonoji with all hnmility, 

 that j^'laciers conM scarcely have been the a.^cnts in the 

 striation of Canadian rocks, the transport of Canadian 

 lK)nlders, or the excavation of Ciinadian lake-basins 

 [except in the ^'reat mountain ran<fes of the continent]. 



" The facts to l)e accounted for an; the striation and 

 polishinjf of rock-surfaces, the deposit of a sluH't of 

 nnstraXitietl clay and stones, the trans[)ort of boulders 

 from distant sites lyin^' to the northward, and the dei)osit 

 on the boulder-clay of beds of .stratified clay and sand, 

 containing marine shells. The rival theories in discussion 

 are — Jlrsf, that which supposes a gradual subsidence and 

 re-elevation, with the action of the sea and its currents, 

 bearing ice at certain seasons of the year; and, sccoitiUi/, 

 that which su])poses the Xorth American plateau to have 

 been covered with a sheet of glacier several thousands of 

 feet thick. 



" The last of these theories, without attempting to 

 undervalue its application to such regions as those of the 

 Alps or of Spitzbei'gen or Greenland, has appeared to me 

 inap])licable to the drift-de])osits ol eastern America, for 

 the following among other reasons : 



"1. It re(pures a series of su[)positions \inlikely in 

 themselves and not warranted by facts. The most ini[)or- 

 tant of these is the coincidence of a wide-spread continent 

 and a universal covering of ice in a tem[)erate latitude. 

 In the existing state of the world, it is well known that 

 the ordinary conditions required by glaciers in temperate 

 latitudes are elevated chains and peaks extending above 



