British North American Plants. 459 



haps all of the Laurentian area in Canada, as well as of con- 

 siderable portions of adjoining areas. I think it the most 

 reasonable conclusion that the whole of this part of the 

 country was of a similar character to what, speaking gene- 

 rally, British Columbia is at the present day, but on a 

 greater scale. — mountainous and rugged, with everywhere 

 high peaks and deep valleys, with frequent plateaus, and 

 with lines of summits so continuous and so connected as to 

 form extended ranges of mountains, — and that, with a 

 somewhat colder climate, individual glaciers occurred 

 everywhere on these mountains, and in their descent car- 

 ried with them ddbris and boulders to the valleys beneath. 

 Some of these glaciers would, as in the Eocky Mountains 

 now, be of comparatively short length, and their action on 

 the rocks beneath them and on the fragments displaced 

 would be correspondingly light ; others would, as in Green- 

 land at the present day, be on an immense scale, extending 

 for very many miles, and be often of great thickness. A 

 universal ice cap over the whole country seems to me an 

 untenable hypothesis, whilst a general mountainous char- 

 acter, with high peaks and ranges, down which glaciers 

 would flow, would explain the phenomena met with at the 

 present day, which are properly ascribed to glacial action. 

 Even at this later day, the whole Laurentian country to 

 the north and south of the St. Lawrence is of this rugged, 

 mountainous character, with indications, as at the Thousand 

 Islands at the outlet of Lake Ontario, that at one time there 

 was a. much greater elevation than now. In fact, the whole 

 inner country lying between the estuary of the St. Lawrence 

 and Hudson Bay is described by explorers as being of an 

 extremely mountainous chaiacter — broken, rugged and 

 impassable, as if the subject of some exceptional convulsion 

 in former ages. 



There are some of the phenomena of glacial action in 

 Canada which go far to show that there also have been, 

 subsequent to, but perhaps before the close of, the glacial 

 epoch, extensive areas of depression, more particularly along 

 and south of the Middle and Lower St. Lawrence and up the" 

 Ottawa Biver, and, perhaps contemporaneously, in the lake 



