418 



region with its outlet through Allistons Branch. This main stream and 

 its principal tributaries were in their old age, and were wandering about 

 the plain, being separated from each other and adjoining stream basins by 

 low divides, except locally where remnants of the preceding peneplain per- 

 sisted. 



Near the end of Tertiary time there occurred another upheaval ; this 

 time of about 800 feet. The streams immediately began to corrade their 

 channels, and in the course of time the main streams cut their channels to 

 base level in their upper and middle courses. In early Pleistocene times 

 there occurred a depression of about 150 feet, which caused the base level 

 portions of the streams to become filled. Wabash and the White rivers 

 show this in an ideal manner. Bean Blossom and Jacks Defeat creeks are 

 excellent examples of smaller streams which have their lower and middle 

 courses filled as a result of the depression of the land. But even these 

 streams are still corrading their channels in their upper courses. Examples 

 of streams which are still cutting their channels, down in the late Tertiary 

 or the Mitchell plain are found in Stouts Branch and Rocky Branch, north 

 of Bioomington, Clear Creek south of Bloomington, and many other small 

 streams reaching into the Mitchell plain. However, such streams are con- 

 fined to the margins of this plain, because of the peculiarity of the Mitchell 

 limestone in its tendency for the formation of sinks and subterranean 

 drainage. Only the major drainage lines cross this formation with an 

 open channel. Beede has treated this subject thoroughly in the paper 

 referred to above. 



In the Flatwoods region the main stream and main tributaries were 

 about as indicated on the map showing the pre-glacial drainage. Consider- 

 able portions of the region, however, were drained by sinks and under- 

 channels, as is characteristic of the Mitchell plain west and southwest of 

 Bloomington. But despite underground drainage, the lower part of the 

 main streams and principal tributaries were cut down to base-level. No 

 doubt many springs came into the streams, being the outlets of the under- 

 ground channels. At the margins underground drainage undoubtdly car- 

 ried water to other streams. Instances of this kind have already been 

 given. 



At this point it is deemed advisable to give some attention to White 

 River, near the lower end of Flatwoods. Collet in his report on the geology 

 of Owen County (Seventh Annual Report Indiana Geol. Sur., 1875), makes 

 note of the extreme narrowness of the White River valley between Romona 



