THE MIDDLE COAL MEASURES 581 
the coal seams are named Wheeler, Panora, and Lacona respec- 
tively. One of the results of the recent work has been to show 
that this presumed lower sequence is in fact a repetition of the 
upper portion, brought about by gentle folding. 
In following down the South Raccoon River and many of its 
tributaries the beds already enumerated are easily recognized." 
A portion of the section is exposed upon Middle Raccoon south- 
west of Linden, where it is seen to be essentially the same as 
originally given by St. John.?, According to the interpretation 
of that author the beds found in passing both up and down the 
river from this point were lower. Below the section already 
quoted he placed a thickness of 145 feet of sandy and variegated 
shales, and below these a series including three seams of coal 
and with a sequence remarkably similar to that found above the 
shales. This hypothesis would require that the beds should 
rise between Panora and Linden enough not only to compensate 
for the fall of the stream but to throw high above the river 
strata deeply buried at the latter point. All dips in the region 
are slight and the one required here would be greater than any 
known to be present. Furthermore, recent studies show that the 
dip from Panora north is in exactly the opposite direction. It 
seems accordingly that the beds at Panora are to be correlated 
with the section already given rather than placed below it. 
Traveling down the Middle Raccoon the beds rise to Red- 
field, at which point a thick, massive sandstone fifty feet thick 
is exposed below them. Below Redfield the sandstone declines 
and the same sequence as was seen at Linden may be made out. 
In the southeastern corner of the county the lower portion of 
the section previously quoted is present overlying a mass of 
variegated shales. These shales are seen in Polk county, east. 
of Dallas, and only the upper part presents any evidence of 
regularity. They extend down to the base of the Coal Meas- 
ures and contain the bulk of the workable coal. The portion 
*Geol. Guthrie county, pp. 436-437. 4Geol. Dallas county, pp. 64-67. 
?See Geology of Guthrie county, p. 430. 
3 See for comparison, Geol. Guthrie county, p. 429. 
