60 STEPPES AND DESERTS. 



son's Bay from those which seek the Gulf of Mexico. Such a 

 dividing line is formed north of Lake Superior by the Missabay 

 Heights, and more to the west by the " Hauteurs des Terres," in 

 which were first discovered, in 1832, the true sources of the Missis- 

 sippi, one of the largest rivers in the world. The highest of these 

 ranges of hills hardly attains an elevation of 1400 to 1500 (1492 to 

 1599 English) feet. From St. Louis, a little to the south of the 

 junction of the Missouri and the Mississippi, to the mouth of the 

 latter river at Old French Balize, it has only a fall of 357 (380 

 English) feet in an itinerary distance of more than 1280 geographi- 

 cal miles. The surface of Lake Superior is 580 (618 English) feet 

 above the level of the sea, and its depth near Magdalen Island is 742 

 (791 English) feet ; its bottom, therefore, is 162 (173 English) feet 

 below the surface of the ocean. (Nicollet, pp. 99, 125 and 128.) 



Beltrami, who separated himself from Major Long's Expedition in 

 1825, boasted of having discovered the source of the Mississippi 

 in Lake Cass. The river in the upper part of its course passes 

 through four lakes, of which Lake Cass is the second. The upper- 

 most is the Istaca Lake (in lat. 47 13', and long. 95 0'), and was 

 first recognized as the true source of the Mississippi in the expedition 

 of Schoolcraft and Allen in 1832. This afterwards mighty river is 

 only 17 feet wide and 15 inches deep when it issues from the singu- 

 lar horseshoe-shaped Lake of Istaca. It was not until the scientific 

 expedition of Nicollet) in 1836, that a clear knowledge of the locali- 

 ties was obtained and rendered definite by astronomically determined 

 positions. The height of the sources of the Mississippi, viz. of the 

 remotest affluent received by the Lake of Istaca from the dividing 

 ridge, or "Hauteur de Terre," is 1575 (1680 English) feet above 

 the level of the sea. In the immediate vicinity, and indeed on the 

 southern slope of the same dividing ridge, is Elbow Lake, in which 

 the smaller Red River of the north, which after many windings 

 flows into Hudson's Bay, has its origin. The Carpathian Mountains 

 present similar circumstances in the proximity and relative positions 

 of the sources of rivers which send .their waters respectively to the 

 Black Sea and to the Baltic. Twenty small lakes, forming narrow 

 groups to the south and west of Lake Istaca, have received from M. 

 Nicollet the names of distinguished European astronomers, adversa- 

 ries as well as friends. The map thus becomes a kind of geographi* 



