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 300 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 Bloomington, 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 
