HOETICULTUKAL SOCIETY. 87 



ocean level at the north, through Hudson's Bay, in British 

 America. 



While, in general, these rocks form the principal watershed, in 

 some parts of the state the later sedimentary rocks rise much higher 

 and give origin to numerous streams which reach the main valleys 

 at a considerable distance from the granitic areas. Freeborn, 

 Faribault, Martin and Cottonwood counties are probably the most 

 elevated in the state, the altitude reaching nearly 1,600 feet above 

 the ocean. 



Enough has been said to show the importance of a knowledge of 

 elevations above the common level at all ascertained points 

 throughout the state. The waters of Lake Superior, for example, 

 are 602 feet above the level of the ocean. Minneapolis is 232 feet 

 above Lake Superior. Half a mile below St. Anthony Falls the 

 level is 118 feet above; at Morehead, 301 feet; at Detroit, 806 feet; 

 Bingham Lake, 811 feet; Worthington is 980 feet above Lake 

 Superior, or nearly 1,600 feet above the level of the ocean. 



The surface varies to a great extent in different localities 

 throughout the state, as, for example, in Houston county, in the 

 southeastern corner of the state, the surface is generally undulat- 

 ing, to rough and hilly. The surface of the rock is gorged by 

 numerous canons, and there are deep, wide valleys, and long 

 ridges. The bluffs that enclose the valleys are sometimes tillable. 

 Some of the valleys are over 500 feet deep; for instance, Root river 

 valley, which is in the St. Croix sandstone region, is over 500 feet 

 in depth, with limestone capping the bluffs. At Houston, the 

 bluffs are 520 feet above the water of Root river, at its ordinary 

 stage. Mt. Tom, at Hokah, rises 530 feet above the flood plain of 

 Root river. In that county there are no lakes, and the streams 

 usually run several hundred feet below the general upland level. 

 The loess loam is very thick in this part o£ the state and is almost 

 impervious to water. Here the Trenton formation is prominent 

 in the southwestern part of the county. 



The general surface in Hennepin county is very different from 

 that of the county just mentioned. Here the Trenton formation 

 predominates ; and we have also the St. Peter and lower Magne- 

 sian formations. We have an undulating, rolling drift surface, 

 with a nearly level general contour. Numerous lakes abound in 

 the western part. The soil differs widely from that found in south- 

 ern Minnesota. Very marked differences are to be found in the 

 various counties of the state as regards soil, climate, timber, 

 stone, etc. 



This state in temperature is said to rank with that of New Eng- 

 land, New York, Michigan and Wisconsin, comparing favorably 

 with western Ohio, Indiana, Illinois and Iowa. The northern or 

 timbered portion of the state enjoys a more equable climate than 

 the prairie districts. 



The numerous lakes distributed throughout the state acquire a 

 high temperature during summer, tending to retain the heat until 

 late in autumn, and thus to check injury from frosts. 



Lake Superior has an area of 11,800 square miles, and this state 



