AND COAL-MEASURES OF MISSOURL 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 toa 
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 Riviére des Péres, 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 Charbonniére, 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. 
