The Tertiary and younger formations of west Tennessee were studied by R. L. Collins and the writer in the summers of 1924 and 1925, and in 1925 Mr. Collins mapped the deposits and collected plants from the Wilcox group. We were accompanied by E. W. Berry, who gave advice on formation boundaries and collecting fossil plants. The Tennessee Geological Survey had mapped the Tertiary of this part of the Mississippi embayment as Porters Creek and Lagrange and had assigned certain beds of sand, gravel, and loess to the Pleistocene. The stratigraphy as here described is in accord with the correlations established by Berry and Cooke in Mississippi and Alabama.
The Tertiary outcrop belt extends from Mississippi across Tennessee into Kentucky, including nearly all the region between the Tennessee and the Mississippi rivers. It is about 115 miles long, about 70 miles wide on the Mississippi line, and about 60 . . .