STRATIGRAPHY OF THE PLANT BEDS. 7 



trates the features of the section at Gihcersou's Ford on the Grand River/ 

 the source of the interesting large phytiferous ironstone concretions col- 

 lected by Dr. Jenney and Dr. Britts. A section of the higher terranes is 

 given by Professor Broadhead, thus: 



Section at GUlcersoti's Ford., Grand River, Mis.^ouri. 



Feet. Indies. 



1. Buff shaly sandstone 5 o 



2. Bine shales 2 



3. Coal 2 



4. Shales and fire clay 14 (; 



5. Coal 



6. Sandstone with Stigmaria 3 o 



7. Shales with lenticular phytiferons beds of iron carbonate 2 



8. Coal in river, reported at 3 o 



The plant-bearing ironstones are said by Messrs. Britts and Jenney to 

 lie in No. 2 of Broadhead's section, i. e., above the third coal, instead of 

 the shales (No. 7) over the first coal, the error of record having probably 

 been caused by the position of the talus. The lower coal (No. 8 of the 

 section), correlated with the Jordan coal, is the one from the roof of which 

 the plants in argillaceous shales at Grilkerson's Ford were collected. 



From the above details it will be seen that all the plants from Henry 

 County, with the exception of those in clay ironstones from Gilkerson's 

 Ford, were obtained from roof shales, which are regarded by the geologists 

 of the State as overlying the same seam of coal, viz, the Jordan coal. The 

 horizon of the clay ironstones is only about 40 or 45 feet higher. 



In some of the broader or deeper mai-ginal basins in the region of 

 Henry County a lower thin coal lies from 12 to 15 feet below the Jordan 

 coal. This coal is exceedingly variable both in quantity and in quality, 

 being sometimes 4 feet thick and of good quality, or full of pyrites and 

 shale, while at other times it is entirely wanting. From pyritiferous con- 

 cretions in the black shale over this coal at Cheatham's mine, near Clinton, 

 Dr. Britts obtained a number of invertebrate fossils, which have been 

 determined by Prof Charles Schuchert, Curator of 'Paleontology in the 

 United States National Museum, as follows : 



Entolium aviculatum (Swallow). Productus nebrasJcaensis Owen. 



ScMzodus curtus M. & W. ? Spirifer rockymontamis Marcou. 



Machrocheilus sp. Eeticularia perplexa (McOhesney). 



Lingula umbonata Cox. Dielasma bovidens (Morton). 

 Productus longispinus Sowerby, 



• Op. cit., p. 17, text figs. 2, 3. 



