KINDERHOOK STRATIGRAPHY 319 
of the Burlington section below the top of the Chonopectus 
sandstone would be beneath the horizon of the Louisiana lime- 
stone.* 
In the recent Iowa? and Missouri3 reports the basal shale as 
exposed above river level at Burlington was considered as about 
the equivalent of the Hannibal shale. At the same time it was 
surmised that this part of the section at Burlington probably 
rested directly upon certain shales found farther north, and 
which were commonly regarded as belonging to the Devonian. 
This, however, was merely a working hypothesis; and opportu- 
nity did not present itself to carry out very far the necessary 
field investigation to either prove or disprove it. 
On this supposition the 235 feet of shale, of which about 
one third is above the river level at Burlington, would represent 
not only the Hannibal shale, but in its lower unexposed part, a 
so-called Devonian shale as well. The recent discovery of a 
rich fauna? considered as composed of typical Devonian types 
gives strength to this idea. Still later Weller’ gives expression 
to something of the same conception when he states regarding 
the occurrence of the Hannibal shales in Iowa, that it is ‘‘ proba- 
ble that the section at Burlington is equivalent, or more than 
equivalent, to the whole of the section as known in Missouri.” 
If we take into consideration the 150 feet of shales below water 
level the stratigraphic evidence now presented goes far towards 
proving the statement. 
The deep-well sections give no indication that the Hannibal 
shales, as they are known at the type locality, change materially 
either stratigraphically or lithologically from Louisiana to Keo- 
kuk. There is yet no reason whatever for imagining that they 
should abruptly thin out entirely between Keokuk and Bur- 
lington. 
*Iowa Geol. Sur., Vol. X, p. 79, 1900. 
2 Towa Geol. Surv., Vol. I, p. 55, 1893. 
3 Missouri Geol. Surv., Vol. LV, p. 56, 1894. 
4Proc. lowa Acad. Sci., Vol. IV, p. 39. 1897. 
5 Trans. Acad. Sci., St. Louis, Vol. X, p. 123, 1900. 
