SURFACE RELIEFS. 



429 



tained tbem directly from the profiles in the oifices of the several com- 

 panies. The list is very full, an altitude being given for almost every 

 section line crossed, and of course the figures have a high degree of 

 accuracy. Except where otherwise stated, the railroad grade is al- 

 ways meant. The remaining tables include a number of altitudes, de- 

 termined by the aneroid barometer, which are, of course, approxima- 

 •tions only. These are selected from a list of many thousand, and 

 apply almost wholly to Dane, Columbia and Sauk counties, which 

 have been chosen because in them the conditions of observation were 

 more favorable, reference points having been accessible during near- 

 ly every day's work, and because, also, in this part of the district 

 the mapping of the geological formations required that the observa- 

 tions should be much more numerous, and consequently more accu- 

 rate, than elsewhere. ^ Numerous determinations of altitude were 

 made in the other counties of the district, but, on account of the dis- 

 tance from railroads or other standards, only a few deserve to be list- 

 ed here. The general altitude of any portion of the district can be 

 obtained from the chapters on local details. 



MADISON TO ELEOY. 

 Chicago & Iforthtvestem Jtailway, 



400,. 



Place. Altitude. 



(bridge 215 



Station 1360, \ sur. Wis. riv., low wat. 170 

 ( sur. Wis. riv., highwat. 180 



1380, Merrimao depot 215 



1460 250 



1*^'^' 1 surface 178 



" iflrmi^^de 292 



^^^' \ top Devil's Nose 378 



1696, surface 464 



" 1702, 429 



" 1783, Devil's Lake, grade . . .386 



ions (Isridge 276 



1^0^' ■) surface 224 



" 1950, Baraboo depot 284 



Lyons depot 282 



Bloom's depot 300 



Ableman's depot 297 



Reedsburg depot 296 



La Valle depot 316 



Wonewoc depot 329 



Union Center depot 862 



Elroy depot 360 



2 Stations 100 feet apart, begmning with East 

 Madison depot as zero. 



1 The aneroid determinations of altitude listed here are beheved to have a considera- 

 ble degree of accuracy. In many cases the same pomt wa^ visited on different clays 

 from .Afferent directions; and in other cases a second barometer was read half -hourly at 

 a fixed point, whilst observations were being made. In this latter way it seems possi- 

 ble to attain great accuracy with the aneroid, especiaUy if such suitable and rehable m- 

 straments are used as those made by J. H. Steward, of London. These have a range of 

 onlv 3.000 feet, and show a variation of 5 feet very distmctly. 



Place. AltiUide. 



East Madison depot 264 



Station 65, ' road crossing 266 



" 130. 273 



" 175, (summit) 80o 



" 262, (summit) 325 



277, deep cut, surface 355 



: surface Catfish marsh 255 



srade 277 



^ 285 



45M^^.:::::::::::;::::ii 



520, Waunakee 341 



570; 341 



nnrj j surfacB 869 



667.]grade 395 



787, Dane depot 477 



9QQ 865 



in„o' ( surface of creek 238 



1002,-j^ade 267 



10.39, Lodi depot 267 



1140 319 



1200, jstt;: :■.■.■.:■.:::■.::: '.255 



' ( surface. 



200 



iQAn i grade ™ 



1300,]furiaoe 1^5 



