The Middle and Upper Eocene of Texas. 
51 
ogdoches and Corrigan to ascertain why such a differeence should 
occur, with the following results : 
The base of the Yegua is found resting on the Marine in the vi- 
cinity of Lanana north of the Angelina , in the banks of which river 
if is well exposed. Along the line of railroad south of the river there 
are few exposures of any kind and the contact between the Yegua and 
overlying Fayette, which is somewhere in the vicinity of Lufkin, or 
just south of that town, is not visible. East of the railroad, how- 
ever, the white sandstones are visible in the creeks, form the country 
rock around Homer, and eastward, toward the Angelina, they 
have their usual development. Similarly the contact of the 
Fayette and Fio is concealed directly on the line of rail- 
way, but can be found to the east and west of it. This con- 
tact should cross the railroad between Diboll and Emporia, and the 
clays of the Frio are well shown in the Neches river section, and 
southward to their contact with the beds now known to be of Jack- 
son age. 
It is proven, therefore, that the deposits between the Angelina 
and the Neches along this line are not, as we originally understood 
them, a single group of clays equivalent to the Yegua, but two groups 
of clay deposits separated by beds of sandstone which, taken together, 
are the direct continuations stratigraphically of the Yegua, Fayette 
and Frio of the western region. So far as known, they are prac- 
tically unfossiliferous in this vicinity. 
The Corrigan beds, as Kennedy called the sands which overlie 
the Frio as now determined, are therefore later than any previously 
recognized Eocene deposits, and the reference of them to the Jack- 
son by Prof. Harris, as well as his reference of the Flemming beds 
to the Oligocene, does not in any way conflict with the earlier deter- 
minations of the western section. 
Having decided this, we made an effort to find similar beds of 
later age west of the Colorado, and to that end careful examinations 
were made along the Colorado itself and several of the streams west 
of it, but in no case did we find a trace of any deposits between the 
real Frio clay and the overlying Oakville. In some places the Oak- 
ville entirely overlaps the Frio and is in direct contact with the 
Fayette. 
It would seem, therefore, that the deposits of Jackson age or Up- 
per Eocene and the overlying Oligocene deposits in Texas are con- 
fined to the territory lying between the Brazos and Sabine rivers, 
and that if they were deposited west of the Brazos they have either 
been eroded or are covered by the Oakville overlap. 
