[PENHALLOW ] NOTES ON FOSSIL WOODS FROM TEXAS 103 
Vaughn (14) takes issue with Kennedy with respect to some of the 
conclusions, but is nevertheless of the opinion that “ The Mansfield 
group, two miles north of Mansfield, is of Lower Claiborne age,” and 
inasmuch as the facies of the flora from this locality is the same as 
of the floras obtained by Lesquereux from Campbell’s Quarry at Cross 
Lake, Louisiana, and by Knowlton from Port Caddo Landing, Texas, 
we must conclude with Vaughn that the horizon is the same in each 
case. He emphasizes the lack of data for a thoroughly satisfactory 
correlation of the plant beds of the Eocene of the Gulf States, a view 
in which he is supported by other investigators already quoted. 
In reviewing the evidence derived from the various geologists who 
have worked in this field, there seems to be a general and well defined 
agreement that the Yegua clays are to be regarded as Lower Claiborne. 
BIOLOGICAL. 
The limited extent of the flora from the Yegua clays does not 
admit of very broad conclusions with respect to its biological aspects, 
nevertheless, there are some features of interest which should be con- 
sidered. 
Of the five species recognized, two are specifically identical with 
previously determined species from the region of the International 
Boundary at latitude 49°, and on the basis of such previous informa- 
tion it has been assumed that these latter represent a northern type. 
Their recurrence at a point about eleven hundred miles to the south 
would therefore point to one of two things—either the very wide 
distribution of the same types over an extreme northern and southern 
range, or the action of water in carrying the remains of trees to a 
more southern region where they became mingled with remains of the 
local flora. The presence of Rhamnacinium in both localities, points 
with very great definiteness to the fact that the genus had a very wide 
northern and southern extension during Eocene time, and that within 
the limits of the genus, the various species exhibited adaptations to 
very diverse climatic conditions. This latter view gains force from 
the fact that Lesquereux observed Rhamnus cleburni in the Eocene 
deposits at Cross Lake in Louisiana (16, 307), together with R. eridani 
of Unger. From these facts it becomes obvious that through the Rham- 
naceæ as a whole, and more particularly through Rhamnus and Rham- 
nacinium, as well as through Cinnamomum, which is not only a 
component of the flora of the Eocene at Port Caddo Landing, Texas, 
but likewise of the Great Valley Group in Saskatchewan (18, 95), there 
was developed a continuity of the flora between these widely 
