UPPER PALEOZOIC (CARBONIc). 251 
Indiana.") ^ , ,t 
Til- • r Lower Coal Measures. 
Illinois. ) 
Middle Coal Measures, 
lowa. I Lower Coal Measures in part. 
Michigan. — Coal Measures. 
Mississippi. " 
rr, [ Coal Measures in part, 
lennessee. 
Missouri. 
Western Kegions. — Upper Carbonic in part. — Carbonic in part. 
Nova Scotia. ~\ 
New Brunswick. V Middle Coal Formation. , 
Newfoundland. j 
This division is sufficiently well defined throughout the Appa- 
lachian area, its floor being the upper sandstone plate of the 
Lower Coal Measures, while its upper stratum immediately un- 
derlies the Pittsburgh coal bed. The Middle Coal Measures is 
the division of greatest economic importance, and is that which 
yields by far the greatest amount of coal in all the areas. It has 
yielded immense numbers of plants and animal remains. The 
mollusks characterizing it persist in the majority of instances to 
the end of the Carbonic in the Interior Basin ; but they all dis- 
appear at the close of this subdivison within the Appalachian 
area, as thenceforward the conditions within that gulf appear to 
have been exceedingly unfavorable, for the most part, to animal 
life. 
The separation from the Lower Coal Measures is made largely 
on physical grounds, but there is a decided change in the plant 
life, for many forms occurring in the Lower Coal Measures do not 
pass to the Middle Coal Measures. 
Lower Coal Measures. 
Synonyms and Local Subdivisions. 
Pennsylvania XII: Serai Conglomerate, Pottsville Conglomerate, Urabral 
in part. 
Virginia and West Virginia XII. : Quinnimont Group, Lower Coal Meas- 
ures. 
Ohio : Lower Coal Measures in part. 
Indiana. "I 
J, J. . r Conglomerate or Millstone Grit. 
Michigan. — Parma Conglomerate. 
Alabama. T 
Mississippi. I . 
rp y Coal Measures in part. 
lennessee. "^ 
Missouri. j 
