205 



Geology of Monroe County, Indiana, North of the Latitude 



OF Bloomington. 



By Albert B. Reagan. 



This work was undertaken as independent research work in strati- 

 graphic geology in Indiana University, in tlie summer of 1903, at tlie 

 suggestion of Dr. J. W. Beede. 



In ISSO Mr. G. K. Green pubhshed a paper entitled "Geology of Monroe 

 County,""* in which he discusses the stratigraphy of the county, giving 

 several sections and lists of fossils and a very generalized geological map 

 of the county. Mr. C. E. Siehenthal has given a lengthy description of 

 a considerable part of the the region here under consideration in his 

 report on the "Bedford Ofilitic Limestone."** Prof. V. F. ^larsters 

 describes the geography of Bean Blossom Creek in an article entitled 

 "Topography and Geography of Bean Blossom Valley, Monroe County, 

 Indiana."*** These papers will be discussed when the subjects with 

 which they deal are taken up. 



GENERAL REMARKS. 



The rocks of this region, with the exception of the Glacial and post- 

 glacial, are Mississippian in age. At the close of the Mississippian period 

 or in the later Carboniferous time the region was raised above the sea. 

 With the exception of a few cases due to local warping its strata dip 

 gently to the southwest. After the area was elevated, the erosive agencies 

 thoroughly dissected the region. The master stream, Bean Blossom Ci'eek, 

 and its numerous tributaries incised for themselves canyon-like valleys. 

 Then on reaching grade, they widened their inner valley floors. On these 

 floors the streams meandered, until a glacier, which crossed the northern 

 part of the county, dammed the lower Bean Blossom and laked the region. 

 Since the retreat of the glacier, side tributaries have, for the most part, 

 recut their channels through the glacial debris to their foi'mer level; and 



•■■■2(1 Ann. Rep. Bureau Statistics and Geology, Indiana, pp. 427-449, 1880. 

 *='-21st Ann. Rep. Geol. Nat. Res. Ind. pp. 293. 

 •■"■■"■■Proc. Ind. Acad. Sci. 1902 (for 1901), pp. 222-237. 



