OF ARKANSAS. 305 



we found another coal-bed six inches thick, showing here the separation 

 of the coal into two strata as it has been remarked at Lee Creek and Frog 

 Bayou. 



The composition of the black fire-clay underlying the Aldrich's coal, 

 and the abundance of iron in the shales above it, indicate a contemporary 

 formation of this bed with the others already mentioned. The hard fire- 

 clay, blackened by roots of Stigmaria, is remarkably developed under the 

 Subconglomerate coal. It is sometimes found alone and without coal, in 

 such places where the combustible matter has not been formed. 



On Hurricane Creek, the same coal is opened at Mr. Newton Carpen- 

 ter's, where it is of the same thickness. 



JOHNSON COUNTY, HORSEHEAD CREEK, MORISSON S, WILMOTH S, BUTT S, LEE S, 



AND OTHER COAL-BANKS.* 



The general appearance of the shales of all these different coal-banks, 

 which are evidently openings in the same coal-bed, are exactly the same 

 as those of the coal of Frog Bayou and James' Fork. The only difference 

 is, that sometimes the shales, as at Morisson's bank, become more bitu- 

 minous, and insensibly pass to brash, near their contact with the coal. At 

 Mr. Wilmoth's bank, where the shales are exposed in a thickness of about 

 twenty feet, they are gray, micaceous, intermingled with pebbles of car- 

 bonate of iron, generally ferruginous, and with few remains of plants. 

 The coal here, twenty inches thick (the same thickness as at the other 

 openings of Horsehead Creek) is better than at Mr. Morisson's bank, 

 where it lies nearer to the surface, and is consequently somewhat rusted 

 and broken by percolation of water charged with oxide of iron. Among 

 the few fossil plants found in the shales are some broken Lepidodendron, 

 especially their leaves ; Neuropteris tenuifoUa, which was seen at every coal- 

 bank examined in Arkansas, and Cordaites flabelliformis, Ung. 



On reviewing with Mr. Cox his section (published page 231 of his first 

 Report), and ascending to the highest point of Horsehead Creek Mountain, 

 we found, by barometrical measurement (1150) eleven hundred and fifty 

 feet of measures of the Millstone Grit series overlying this coal. The base 

 of the series is here, as elsewhere in Arkansas, a compound of reddish and 

 sometimes dark brown argillaceous shales, and the top a conglomerate 

 sandstone. The hard, coarse sandstone covered with vermicular concre- 

 tions (a peculiar kind of impressions, which have been mentioned in the 

 first Eeport, page 114) is in place near the top of the Horsehead Creek 

 Mountain. I had thus a good opportunity of examining these curious 



* See descfiption of these coal-banks in Mr. Cox's first Report, page 231. 



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