306 The A)iieric(ni Geohxjisf. NovcmbiT. i895 
111 this vicinity lignite is extremely abuiulant. We know 
these beds are Eocene, but to what stage of that series to re- 
fer them is a difiiciilt question. The opinion was expressed 
by the writer in a recent article that they were of Lignitic 
age.* Unfortunately the determination of the age of our Eo- 
cene deposits depends entirely upon the fossil animal remains, 
because no systematic study has been made of the floras. Di- 
visions founded upon mere lithologic characters are insutli- 
cient, as lignitic strata are found in every division of the 
Eocene. At present the determination of the age of any part 
of the lignitiferous Eocene of the Gulf states depends entirely 
upon a minute knowledge of the stratigraph}' of the surround- 
ing regions in which marine fossils have been found. On k 
blue-print map which has recentl}^ been distributed by W. 
Kenned}^ entitled "Map showing Areal Distribution of the 
Eocene Tertiary in East Texas, Compiled from Geological 
Surveys," it appears that most of the beds devoid of marine 
fossils and consisting of lignitic strata have been designated 
as of "Lignitic" age. The present writer doubts the correct- 
ness of this. 
The reason for considering the Port Caddo section of Lig- 
nitic age is because Mr. Harris in his report on the geology of 
southern Arkansas has indicated the Lignitic-Claiborne as 
running to the headwaters of the lakes developed along the 
Red river. His work was based upon both careful paleonto- 
logic work and held study. The streams in northwestern 
Louisiana and the adjoining part of Texas, i. e., Red river, 
Cypress bayou and the other streams of that type, have cut 
far down into the fornuitions upon which their courses lie. 
The elevation at Jefferson, Texas, is 2H1 feet ; at 8hreve])ort, 
Louisiana, it is 185 feet. It would seem most probable that 
into this low-lying <'()untry along these streams where there 
had been so much erosion that we would find an extension of 
the Lignitic from Arkansas. Capping the highlands sur- 
rounding this eroded area, to the east, south and west we have 
renuiins of the marine (lower Claiborne) beds. In the vicinity 
of Daingerlield, which is northwest of Port Caddo, at an ele- 
vation of 400 feet, there is an area of the marine be(ls.+ At 
*Amer. Geol.. vol. XV. p. 209, Apiil, ISiT). 
tKenu(Hly''a luai). 
