144 



TRANS. ST. LOUIS ACAD. SCIENCE. 



sas City and between, Glasgow and Jefterson City, the westward 

 bending of the 8° and 8° 30' lines in the Osage Valley as com- 

 pared with the 9° line in the same latitude and the remarkable 

 Hexures in eastern Iowa, are all in harmony with it. 



A comparison of these lines with the tables of declination given 

 in the two reports will show the accuracy with which the facts are 

 represented. 



The determinations made at Jefferson City (see descriptions 

 of stations, pp. 121-125) are likewise of interest in this con- 

 nection. 



In the following table d represents the distance (in yards) of the 

 observations from the middle of the river ; H^ the horizontal 

 intensity, and d the observed declination; //, the elevation above 

 high water. 



Making all due allowance for possible influence due to disturb- 

 ing causes at stations a and (5, there remains strong proof of a 

 regular and marked change in these values as we recede fi'om the 

 river, and a more minute local survey is therefore contemplated 

 in order to determine the facts beyond question. 



