l_^2 TRANSACTIONS OF THE ILLINOIS 



While it is not my purpose to go into an elaborate analysis of the 

 subject, which is too great an undertaking for an essay adapted to the 

 present location, T shall aim to present certain salient features of note- 

 worthy interest, and direct attention to their practical bearing upon the 

 subject that calls us together in annual convention — Horticullurc — inci- 

 dentally, before leaving it, referring to an external agency as affecting 

 results that might otherwise follow as general conclusions. 



The Topography of the State is so nearly a plane that it is com- 

 monly so considered. Some data u})on this jloint will be interesting. 

 The Mississippi river at Dunleith is three hundred fifty feet above its 

 level at Cairo, and twenty-three feet above lake Michigan. Between 

 lake Michigan and the Mississippi river at Dunleith, the country grad- 

 ually rises to the westward, until in the vicinity of Scales Mound, which 

 is the most elevated point in the State, except the adjacent mounds. 

 The Illinois Central railroad, at one point there reaches an elevation of 

 eight hundred five feet above low water mark at Cairo, and Scales 

 Mound two hundred eleven feet higher, or one thousand sixteen feet 

 above the Cairo datum ; making it about one thousand, two hundred 

 ninety feet above sea level. 



The mounds of this portion of the State are elevations of the orig- 

 inal strata of Niagara and the Cincinnati group left remaining after the 

 drift movement had carried away a corresponding thickness of the same 

 formations over a large area of territory. Mounds corresponding with 

 these are found in what is almost the lowest part of the State — the region 

 of Big Muddy river, in Franklin and Williamson counties, formed in 

 the same way, being elevations that resisted the erosion of the drift 

 movement, but totally unlike those of the north, as ihey are sandstones, 

 shales, and clays of the coal measures. 



To represent the surface of the State by a profile, from North to 

 south, if the vertical and horizontal scale were alike, it would be simply 

 drawing a straight line slightly descending from the Wisconsin state 

 line to Cairo, with a slight flexure upward from a point sixty miles north 

 of Cairo for the next forty miles South, and then continuing the direc- 

 tion of the first line ; and yet so much and constant is the deviation 

 from a plane to a direct line of descent that grades of forty feet per 

 mile are common on our railroads north and south as well as east and 

 west. Even then considerable excavation has been done to avoid 

 higher grades. 



Ridges that are of considerable elevation, and many miles in length, 

 cross the prairie region and have a local influence. 



The mounds referred to, in northwestern Illinois, are a part of a 

 great Silurian upheaval, forming a ridge that runs in a southeasterly 

 course in a very direct line from Minnesota nearly across Illinois; the 

 central line of which runs near Scales Mound, Grand Detour, Utica, 

 and Urbana, at which point it has so far faded out as fo be only trace- 

 able by a slight disturbance of the coal measures. 



Throughout most of its course it would not be noticed by any dif- 



