Division of the Kansas Coal Measures. 



KV ERASMUS HAWORTH. 



So many different plans have been followed by geologists of the 

 Mississippi valley in dividing the Coal IMeasures that one who is 

 laboring in a new field has no positive criterion by which to be guided. 

 By some the Coal Measures have been divided into two divisions, 

 the Lower and the Upper; by others into three, the Lower, Middle 

 and Upper. Rarely have the same division lines been made, or the 

 same bases of classification been used, so that we are left in doubt in 

 almost all instances why any particular division was made at any par- 

 ticular place. According to the different State Reports of our nearest 

 neighbor to the east, Missouri, Broadhead used a sandstone with no 

 special characteristics as the division line between the Lower and 

 Middle Coal Measures, and a second sandstone of equally unimport- 

 ant characteristics for the division line between the Middle and 

 Upper. Why these particular sandstones should be chosen rather than 

 other formations he does not say, neither are we informed why the 

 whole Coal Measures should be divided into tliree divisions rather 

 than into two, or four, or any other number. Winslow in his more 

 recent Report does not attempt to divide the Missouri Coal Meas- 

 ures at all, but he does not take ground against it, so the reader is 

 left in doubt to a certain degree regarding his views on the subject. 

 But Dr. Keyes, in volume II of the Iowa Report, 1894, brings up 

 strong objections to the older method of division, and suggests what 

 seems to be a better basis of division, provided one is used at all. 

 We shall have occasion to refer to this later in this paper. 



It would seem reasonable to assume that in all matters of divisions 

 and sub-divisions of the Coal Measures the same general methods 

 be adopted and the same principles followed that are used in dete"r- 

 mining the number and locations of the sub-division lines of any other 

 great geologic formation. The custom of geologists of all countries 

 is practically the same in this. At least one of two conditions is 

 always required to make a division which in application is more than 

 local. One of the conditions is that there must have been a break 

 in the succession of formation, a time break, indicated by general 

 unconformity, such as is produced when a surface is lifted above 

 ocean water and more or less eroded before later formations are 

 placed upon them, or when considerable orographic niovei^ent has 



(291) KAN. UNIV. QUAR. VOL. Ill, NO. 4, APRIL 1, 1895. 



