Central Iowa Section of the Miss. Series. — Bain. 323 
eastern Iowa is typically exposed at Burlington, where the 
layers referred to the formation are:* 
Feet. 
6. Rather soft, buff limestone; probably somewhat mairne- 
sian, apparently sand^' locally 5 
5. Gray ool i te ... 4 
4. Soft, fine-grained, yellow sandstone, highly fossil ift-rous 
3. Gray, iminire limestone, fragmentary, often witli an 
oolitic band below !)-]3 
2. Soft, fine-grained bluish or yellowish clayey sandstone, 
passing into sandy shales in places 20-30 
1. Blue clay shales, fossiliferous, exposed above water 50 
The Maple Mill shales may be correlated with number one 
of this section. The English River gritstones contain a fauna 
presenting affinities to that of number four, which is the "yel- 
low sand" from which the principal collections of Kinderhook 
fossils have, in Iowa, been made. Worthenf considered the 
beds which we have called the Wassonville limestone as the 
equivalent of the oolitic layer, number five. 
The Choteau limestone of Missouri may be represented in 
numbers four and five of the Burlington section. The re- 
mainder of that section is probably the equivalent of the Han- 
nibal shales. The lowest member of the Kinderhook, the Lou- 
isiana limestone, is not represented at the surface in Iowa, if 
indeed, it be present at all. 
The rocks now referred to as Kinderhook were first studied 
in Iowa by Owen and were by him and his immediate success- 
ors considered to be Carboniferous. Later they were consid- 
ered by Hall and his fellow workers to be Devonian and were 
correlated with the Chemung of New York. In 1861 Meek 
and Worthen;]; recognized their Carboniferous affinities and 
proposed the name Kinderhook for all the strata between the 
base of the Burlington and the Black slate, quite generally 
recognized throughout the upper Mississippi valley. The up- 
per line of delimitation is not difficult to recognize in Iowa, 
but owing to the absence of the "black slate" the lower limits 
are not so clearly defined. 
The line of juncture between the Devonian and the Kinder- 
hook is nowhere exposed in this state. While the exact divis- 
*Keyes: Bui. Geol. Soc. Am., iii, 2m, 1892. 
fGeol. of Iowa, vol. i, p. 230, 1858. 
:tAm. .Tour. Sci., (2), xxxii, 228, 18(51. 
