HENDERSON COUNTY. 285 



umbrosuc, 8. aubventricosus, 8. glyptus, Dorycrinus cornigerus, D. dicornis, Stegano- 

 crinus pentagonus, Platyerinus plenus, Zeacrinus, species nearly allied to Z.elegans, 

 Cadaster stelliformis, Granatocrinus Norwoodi, G. Sayi and Pe.ntremites elongatus. 

 In addition to these, the following species of brachiopods were obtained : Spirifer 

 plenus, 8. Grimesi, Productus semireticulatus, var., Burlingtonensis, Ohonetes Illi- 

 noiensis, OrtMs Swallovi, 0. Michelini ; and of other divisions, Platyceras, Metop- 

 tomn umbella, EvacMnopom sexradiata and HadrophyUum glans. This is not a 

 complete list of the fossils of this group found in this county, but comprises the 

 most common forms. 



Kinderhook Group. This group, which underlies the Burlington limestone, 

 is exposed in but lew places in Henderson county. Across the river, at Bur- 

 lington, the beds of the group comprise variable strata of shales, gritstones and 

 oolitic limestone. On this side, the oolitic limestone and gritstone beds are 

 wanting, and the group is represented by shales only, which are commonly 

 argillaceous, though occasionally calcareous or arenaceous. The shale is usu- 

 ally in very thin layers, and of little or no value. There is a partial exposure 

 of these beds in section 24, township 9, range 4, along Ellison creek, which 

 gives the following succession, commencing below the Drift: 



FEET. 



Burlington limestone 24 



Shales of Kinderhook, to the surface of the stream 22 



These beds outcrop for some distance along the Mississippi bluffs, but are 

 mostly hidden by the talus of the sloping hills. A short distance southeast of 

 Sagetown, a boring was made a few years since, for the purpose of obtaining 

 water for a distillery. I am indebted to Squire Rice, of Sagetown, who had 

 the work done, for the following section: 



FEET. IN. 



1. Chert and clay 40 



2. Bluish clay shale 120 



3. Black slate 7 



4. Bluish clay shale 162 



322 7 



Considerable of the shale was calcareous, but did not, at any point, become 

 limestone. At a depth of three hundred and twenty-two feet, the character of 

 the rock had not changed, and the work was abandoned, for the time, without 

 having obtained water. This work was commenced in the Drift at or near the 

 base of the Burlington limestone. 



Southeast of Oquawka, these shales are exposed on Mr. Bosler's farm, at a lit- 

 tle run, about twenty feet above the bed of Henderson river. Along South 

 Smith creek, section 24, township 11, range 5, fifteen feet of these beds may 

 be seen between the Burlington limestone and the creek bottom. At this 

 locality, there is a band of calcareous clay shale, from six to ten inches thick, 

 just below the limestone. These shales, where exposed, seem to be destitute 

 of fossils, none having been found, after a close examination. 



