374. Mr. Lyell on the Coal Field of Tuscaloosa, Ala. 
30 to 40 miles northeast of Tuscaloosa, may be said to consist of 
‘three subdivisions: 1st, the productive coal measures ; 2d, quart- 
zose grit, used for millstones, with schistose sandstones and 
slates ; 3d, limestone and chert. The first of these, or the pro- 
ductive coal measures, consist of the usual white sandstones and 
grits, so common in all coal fields, with greenish and gray mica- 
ceous sandstones, and some ripple-marked. slabs of yellow sand- 
stone, with Calamites. Associated with these, are shales and — 
clays, with seams of coal, the thickest of those which I saw 
being about four feet, but a ten foot seam has been discovered 
sixty miles farther to the north. I saw a thickness of many hun- 
dred fect of this formation, but have no data for estimating its 
enitiré vertical extent. 'T’o the above succeeds, in the descending 
order, a great deposit of quartzose grit, used for millstones, which 
-yesembles in position and mineral character, the millstone grit of * 
the north of England, and perhaps occupies the place of the fun- 
dainental conglomerate of the great Apalachian coal field. It 
passes downward into thinly laminated sandstones, and dark slates 
of small thickness. ,Under this group lies a formation of lime- 
stone, usually blue, with white veins of carbonate of lime, and 
swith much chert and hornstone intermixed. In the pure lime- 
stone, which is fetid, when broken, no fossils have been found, 
but in some of the associated siliceous beds, Prof. Brumby has 
obtained Encrinites, Producta, Orthis, and one or two corals, which 
have not yet been determined, but the genera which I saw, are 
such as might belong to the carboniferous limestone. In some 
of the inferior beds of limestone, there is a great mixture of iron, 
and throughout the range of this formation, there has been traced 
an enormous mass of brown hematite, which seemed to me to 
constitute, where I examined it at Murphy’s, 30 miles from Tus- 
caloosa,a regular bed, rather than a vein. From the abundance, 
accessibility and richness of this ore, its proximity to the coal 
field and to the navigation of the Tombecbee River, I can hardly 
doubt that, like the coal itself, it is destined, at no distant day, 
be a source of great mineral wealth to Alabama. I may a 
mention that large specimens of pure galena, obtained from this 
limestone formation, have been shown me by Prof. Brumby, who 
found them in the counties of ‘Tuscaloosa, Bibb, Shelby, Jeffer- 
son, and Blount, as also in the Tennessee valley, in Alabama ; 
CUE AIS DEBE cet ager, ee 
