184-6.] LYELL ON ALABAMA COAL-FIELDS. 279 



Tombecbee River from Tuscaloosa, a navigation of about 400 

 miles. This coal is procured from the neighbourhood of Tusca- 

 loosa, a place situated near the centre of Alabama, and more than a 

 hundred miles further south in a direct line than the southern limit 

 which I had assigned to the Appalachian coal-field, which I sup- 

 posed to terminate near the great bend of the Tennessee River. 



The fact of coal occurring near Tuscaloosa had been previously- 

 mentioned to me by Mr. Conrad, but he was uncertain respecting its 

 age ; and the circumstance of its occurrence near the Falls of the 

 river, not far from the northern outcrop of the cretaceous strata, 

 together with the fact of its quality being preferred to all other coal 

 for the manufacture of gas at Mobile, made me suspect that it might 

 prove to be of the age of the Richmond coal, which is also bitumi- 

 nous, situated near the Falls of the James River, and which, as 

 Professor W. B. Rogers has pointed out, is newer than the ancient 

 carboniferous series. 



In order to determine on the spot the question in regard to its 

 age, I ascended the Tombecbee from Mobile to Tuscaloosa, where 

 at the University I found Professor Brumby, who had examined 

 with considerable care the geographical boundaries of the produc- 

 tive coal-measures and the structure of the region. With him I 

 made an excursion to some of the pits, or rather open quarries of 

 coal, where the edges of the beds of several seams have been dug 

 into by different individuals entirely ignorant of mining operations, 

 but with no small success, the quality being good at the point of the 

 natural outcrop. I found the coal-seams covered everywhere with 

 beds of ordinary black carbonaceous slate full of impressions of more 

 than one species of Calamite, with ferns of the genera Sphenopteris 

 and NeuropteriSi and impressions of Sigillaria and Lepidodendron. 

 In some of the beds Stigmaria has also been met with not unfre- 

 quently, and I recognise a specific identity between several of the 

 most common of these coal plants, and those which I formerly ob- 

 tained from the mines of Ohio and Nova Scotia. I also observed the 

 complete difference between these fossil plants and those most charac- 

 teristic of the newer or Virginian coal-field near Richmond, which 1 

 lately had an opportunity of examining on my way south. The strike 

 of the coal-beds in Alabama is also, where I have seen them, north- 

 east and south-west, agreeing with the general direction of the Alle- 

 gany Mountains, of which, geologically speaking, they are evidently 

 a southern prolongation. They are, in fact, portions of the great 

 Appalachian coal-field, with all the same mineral and palaeontological 

 characters, the beds having been bent into similar ridges to those of 

 the Alleganies, with corresponding dips to the north-west and south- 

 east ; and we have no reason to suppose that Tuscaloosa, in lat. 33° 

 10' south, is the extreme southern limit of the formation, for the 

 carboniferous strata are merely concealed from observation south of 

 this point by the lower gravelly and sandy beds of the cretaceous 

 group which extends to Tuscaloosa. 



In the eastern part of Alabama, a zone of hypogene or granitic 

 rocks separates the tertiary and cretaceous strata of the Atlantic 



