AND COAL-MEASURES OF MISSOURI. 139 



ordinary thickness, but also for the peculiar character and structure of the coal 

 itself, together with the mineral insinuations which invade it. 



The lightness of this combustible is such, that before imbibing water, it will float 

 upon that fluid, indicating a specific gravity actually less than 1. In its structure, 

 fracture, and lustre, it has an appearance intermediate between cannel coal and the 

 dull varieties of asphaltum, but it contains 31 per cent, less volatile gases than 

 pure bitumen, and from 5 to 10 per cent, more volatile matter than the ordinary 

 varieties of the bituminous coal of the Western coal-fields. 



At the pit west of Marion, this coal assumes a cuboidal, and even a subcolumnar 

 structure, somewhat analogous in miniature to basaltic trap; while, at the same 

 time, a network of pyritiferous ores of zinc and iron have ramified its joints and 

 fissures, and appear often in brilliant crystalline forms, — the whole bearing evidence 

 of great local disturbance, igneous action, and gradual consolidation under heavy 

 pressure. It appears, indeed, altogether probable, from the peculiar character of 

 the coal, its structure, and great local thickness, that it has been subjected to a 

 sufficient degree of heat to have fused or semifused the mass, under a pressure that 

 prevented the escape of the volatile gases, transferring it, at the same time, either 

 in this condition or by sublimation, from its original bed, into some wide, adjacent 

 fissure, formed by disruption of the strata, where it has then very gradually passed 

 into the solid state. Its uniform occurrence in close proximity to an abrupt 

 change in the geological formation of the adjacent country, and the sudden eleva- 

 tion of Protozoic rocks, about to be noticed, together with the highly inclined posi- 

 tion of the coal itself, furnishes abundant proof that it has been implicated in the 

 remarkable disturbances which have convulsed the whole of the surrounding country 

 subsequent to the carboniferous era. 



On approaching the waters of the Manitou and Bonne Femme Creeks, the lime- 

 stones of the carboniferous epoch are invaded from beneath by the great uplift of 

 Magnesian Limestones, heretofore noticed as bounding, for some distance on the 

 southeast, the Iowa and Missouri coal-fields, and become, in a measure, confounded 

 with them. This mixed formation composes, in connexion with some intercalations of 

 sandstone, those high mural escarpments in the vicinity of the confluence of the 

 Gasconade and Missouri, and at Tavern Rock ; which attain, at the latter locality, 

 where the Meramec approaches within six or seven miles of the Missouri, an eleva- 

 tion of over three hundred feet. (Sections No. 9 to 4, M, inclusive.) 



This great axis of Magnesian Limestones separates (by a zone gradually widening 

 as it approaches the Mississippi, to nearly a hundred miles) the outcrops of coal on 

 the Osage, Manitou, and Cedar Rivers, in Cole and Calloway Counties, from the 

 coal-pits opened on the waters of Riviere des Peres, in St. Louis County. Along 

 this portion of the Missouri Valley, it is only on the summits of the highest ridges 

 that any rocks can be found referable to the carboniferous period. Rocks of this 

 age set in again, however, near St. Charles and Manchester. Here the sections are 

 again composed solely of carboniferous limestones ; and a section (No. 3, M) obtained 

 near Charbonniere, presented shales and grits surmounted by productal limestone, 

 and underlaid by a five-foot seam of coal, having near its centre, however, a parting 

 of a, few inches of argillaceous clay, the whole resting on the St. Louis limestone. 



