260 The American Geologist. October, 1895 
the schizochroal (PJiacops) and holocbroal (^4.s-fy>/t((.s) groups. The i)res- 
once of appendages upon the segments of the thorax and jiygidium is 
established, though those of the former are much obscured by the thick 
fringe of the exopodites. A similar fringe accompanies the exopodites 
of the pygidium, while the endopodites are broad and phyllopodiform, if 
less strikingly so than in Triarthrus. , j. m. c. 
Report on the Coosa Coal Field, loith sections. By A. M. Gibson* 
iGeological Survey of Alabama, 143 pp., one plate. Montgomery, 1895.) 
Alabama in 1893 ranked fifth in coal pi-oduction in the United States, 
with a total of over five million tons. This tonnage comes from four 
different fields having the following areas as given by state geologist E. 
A. Smith. 
Warrior field: 
Plateau region 2,275 sq. mi. 
Basin region 4,955 sq. mi. 
Lookout mountain 580 sq. mi. 
Cahaba field 435 sq. mi. 
Coosa field 415 sq. mi. 
The Geological Survey of Alabama has devoted a good share of its re- 
sources to an investigation of these coal fields. T. H. Aldrich in 1875 
gave a history of early mining in Alabama, Mr. Squire has reported on 
the Cahaba field, and Mr. McCalley upon the Warrior field as a whole 
(1886) and upon the plateau region alone (1892), and Gibson has pub- 
lished a report on the Blount county deposits. 
- The present report by Mr. Gibson deals with the Coosa field alone. 
This is the smallest of the Alabama fields and contains, according to 
his surveys, some 345 sqviare miles of productive area. It stretches in 
a long narrow belt having an average width of five to six and a length 
of some sixty miles. It lies mainly in St. Claii'and Shelby counties 
with a slight prolongation into Cahun".; The field is a narrow synclinal 
valley bordered by high marginal mountain rims and is in addition, as a 
result of transverse faults, traversed by fiumei-ous mountain ridges 
which give it a very rugged topography. The Coosa field is divided in 
eight basins : the Ragland, Fairview, Coal City, Black Ankle, Kelley's 
Creek, Howard, Peavine Creek, and Yellow Leaf; each of which is con- 
sidered in detail. The principal development so far has taken place in 
the Ragland and Coal City areas. It was from the former that the Con- 
federate ordnance works at Selma drew their supplies. The beds are 
not thick, but run regularly and seem to be of - considerable uniformity. 
The coals are of good quality, free burning, low in sulphur and well 
adapted to steam and grate use. The Coal City and Ragland seams 
furnish an esjjecially good quality of coke. At the latter place the coke 
is made from the fine coal after being washed. 
In the report a large number of workable beds are noted and, while 
the present peculiar economic conditions confine the active work of min- 
ing to two points only, in the future an important development may be 
confidently expected. h. f. b. 
