OF ARKANSAS. 303 



formations, just as the water-lily or the spatterdock does the swamps of 

 our time. The relation of this plant is still uncertain. Some of the 

 numerous and large fruit, found in the shales of the coal, have been 

 referred to this species, apparently without reason ; for the shales which 

 have preserved the greatest quantity of these leaves contain scarcely any 

 remains of fruits. 



SEBASTIAN COUNTY, JENNY LIND PRAIRIE. MR. GREEN S COAL-BANK. 



From the strata of red ferruginous or ochreous clay shale, which gene- 

 rally mark the base of the Millstone Grit series in Arkansas, and which 

 crop out at the base of the hills bordering the prairies, the position of this 

 coal, as Subconglomeratic, becomes at once evident. As the shales of this 

 coal do not show the same general appearance as at the other localities 

 where it was examined, this stratigraphical conclusion is of some value. 

 The shales look like a compound of yellow clay and ironstones mixed to- 

 gether. They break crosswise or perpendicularly rather than horizontally, 

 and are separated by irregular bands or thin veins of clay more deeply 

 colored with oxide of iron and extremely brittle. The fossil plants con- 

 tained in this peculiar kind of shale are tolerably numerous, but they are 

 generally broken and difficult to determine. The species which would be 

 recognized, and which are enumerated in the table, strengthen the conclu- 

 sion which places this coal at the same geological horizon with those 

 above. The coal, here, is four and a half feet thick, and has two clay part- 

 ings of about one inch each. But the top coal, for about one foot of its 

 thickness, is a shaly or brashy coal of little value as a combustible. It 

 looks like a brittle black shale intermixed with lamellae of coal-matter and 

 full of broken remains of plants difficult to determine. The presence of 

 this brash coal is still a character which in some places may help the iden- 

 tification of the Subconglomeratic coal. In Indiana, the whole thickness 

 of the bed corresponding to this one by its position, is at times only a com- 

 pound of brash or black bituminous thin layers of shale, separated by 

 alternate thin layers of coal. In Kentucky, the Subconglomerate coal bed 

 is generally, if not always, overlaid by a few inches of this kind of brash, 

 which has to be separated from the true coal as useless. 



JAMES FORK OF POTEAU. MR. MORROW S COAL-BANK. 



At this place, there is not any difference in the appearance and the 

 nature of the shale from what we described at Frog Bayou or at Male's 

 coal-bank. The shales are gray, hard, somewhat micaceous, intermingled 



