269 
THe Huron Group In WESTERN MoNROE AND FJASTERN 
GREENE CountiEs, INDIANA. 
By F. C. GREENE. 
The opening of the right-of-way of the Indianapolis Southern Railway 
between Indianapolis, Indiana, and Effingham, Illinois, presented an un- 
usual opportunity for the study of the so-called Huron group, west of Bloom- 
ington, Indiana, in western Monroe and eastern Greene counties. The 
fluron group is the youngest formation of the Mississippian of Indiana. 
The name Huron was first apyplied by Dr. Ashley in his paper on the 
Lower Carboniferous Area of Southern Indiana. 
The type locality is at Huron, Lawrence County, a station on the B. & 
O. S.-W. Railway. According to his definition, the boundaries of the Huron 
group are fixed at the base of the lowest sandstone in the group and the 
unconformity at the top which marks the division between the Mississip- 
pian and Pennsylvanian. The discussion of his reasons for so drawing 
the limits at these points may be found in his report and will not be re- 
peated here. However, as the name Huron is preoccupied’, it must be 
replaced by another, and it is here proposed to substitute the name Chester, 
as the group can be correlated with the upper Mississippian of Illinois 
or Kentucky. 
Blatchley gives a concise summary of the formation.* He says, “In 
Orange County, where the Huron group is perhaps the most typically ex- 
posed, it is represented by a lower limestone, a lower sandstone, a middle 
limestone, an upper sandstone and an upper limestone. . . . 
The lower Huron limestone is a compact, smooth-grained, ash-gray to 
blue limestone, which varies from five to eight feet in thickness. In struc- 
ture it is a close-grained, fine-textured, non-crystalline stone, breaking with 
a sub-conchoidal fracture. ... . 
1 Ashley, G. H., Dept. of Geol. and Nat. Res. of Ind., 1902. 
2In the Rept. of Progress in 1869, Geol. Survey of Ohio, Part I, p. 18, Dr. S. 
W. Newberry proposed the name Huron for a shale formation of the Devonian of 
Ohio. 
SBlatchley, W. S., Thirtieth Ann. Rept. Ind. Dept. Geol, and Nat. Res., pp. 144- 
145. 
