C. A. White on the Iowa Coal-measures. 331 
Art. XXXVI.—Character of the ct crc <= im 
Iowa Coal-measures upon the Older Rocks; by C, 
Wairer, M.D.* 
Tue paleozoic rocks of Iowa, with the exception of those 
- one period, all rest conformably upon each other, and show 
regular recession to the southwestward in the Brebiio’ of 
thei general dip, the trend of their outcrops being quite uni- 
ormly in a southeasterly and northwesterly direction. 
exceptional unconformability referred to is that of the lower 
oal-measures upon the Subcarboniferous rocks, and in connec- 
tion with the same, the unconformability of some “of the members 
of the Subcarboniferous group upon the others. Succeeding 
this unconformability, the sub-epochal divisions of the coal 
measures again show the same gradual recession to the south- 
westward, together with a similar general direction of trend 
that the older rocks do. 
Thus in the Iowa coal field, we always find the lower Coal- 
measures at the border ; next in order comes the middle when 
that discrimination has been made,} and then the upper, still 
farther within the field. 
- For the purpose of being more clearly understood, the fol- 
lowing names and numbers are given in the asce cending order, 
of the. numbers of the Subcarboniferous period as at presen esent 
a by the writer to be developed in the Mississippi 
valley. 
a 
® 
V. Cuesrer LimesTone,{ with its sandstones above and 
below. (Kaskaskia limestone of Prof. Hall 
IV. St. Louis Limestone (Concretionary limestone of Dr. 
Owen, and in part Warsaw limestone of Prof. Hall.) 
III. Keokuk Limestone. 
II. Lower and Upper Burlington Limestone. 
I. Kinderhook beds of Meek and Worthen. (Referred to 
Chemung gronp by Hall and others.) 
No rocks referable to the Chester limestone epoch wars oh 
been found in Iowa, and wherever the base of the lower 
* In advance of his final report upon the Geology of 
Pe = the writer’s communication to this Journal, published July, 1867, the 
further investigations by Mr. St. a and ooo the Iowa coal f ‘field 
