14 GLACIAL AND SURFACE GEOLOGY OF THE PACIFIC COAST. 



these is in North America, the other in Europe. The former is a region 

 of both great and small lakes ; the latter of small ones exclusively. The 

 North American lake system is the most extensive one in the world at the 

 present time, although it may possibly have been surpassed, at a not very 

 remote geological epoch, by that of Central Asia. 



The geographical position of the region of country occupied by the great 

 system of North American lakes is pretty well known, especially in its south- 

 ern portion, although there is no map on which anything like the entire 

 number of these bodies of water is shown ; while for most, even of the largest, 

 at best but a rough approximation to their outlines can be given. It may be 

 well, therefore, to call the attention of the reader to the foct that, all along 

 a line stretching in a northwesterly direction from Lake Superior to the 

 Arctic Ocean, there are not only numerous, but almost innumerable, bodies 

 of water, several of which are but little, if at all, inferior in size to even the 

 largest of our so-called " Great Lakes." The number of lakes in this region 

 is quite unknown ; but a belt of country 2,000 miles long and fully 500 wide 

 is a labyrinth of them, and they are of all dimensions, from mere ponds to 

 bodies of water hundreds of miles in circumference. So too in the opposite 

 direction, or along the range of the Laurentian Mountains, northeasterly 

 from Lake Huron towards Labrador, there are unnumbered expanses of fresh 

 water, mostly of moderate size compared with the Great Lakes, but many of 

 them having a considerable area. These Canadian lakes have not yet been 

 accurately mapped; but more than a thousand of them had, some fifteen 

 years ago, been more or less explored by the Geological Survey. In fact, 

 tlie whole region northwest of the St. Lawrence, as fiir as Hudson's Bay, 

 is covered with lakes and lake-like expansions of the rivers, so that there is 

 free access by canoe to every part of the countiy, with occasional portages, 

 or " carries," around the rapids in the rivers. 



In this lake region may be included a large part of Maine and the north- 

 ern portion of New Hampshire, as well as of Vermont and Northeastern New 

 York. 



In striking contrast with what has been stated above, we find the region 

 immediately south of the Great Lakes to be one almost entirely destitute of 

 lakes. Everywhere, from the water-shed separating the waters fiowing into 

 the Susquehanna and Ohio from those running northwards, as far south as 

 the Gulf of Mexico, there is an almost entire absence of lakes; indeed, it 

 would be hardly i)Ossible to imagine a greater contrast, in this respect, be- 



