NACOGDOCHES COUNTY. 285 



of red clay to the summit of the hill. In both these localities small frag- 

 ments of iron sandstone two inches thick are found at intervals. From 

 Simpson's Hill was taken also a small fragment of iron conglomerate. 



RELATION OE STRATA. 



To avoid repetition, it may be stated that the general section is similar to 

 that described under Panola County from Nos. 1 to 19, with the following 

 exception : 



In the southern portion of this county the lignitic boundary seems to have 

 been either an irregular serrated line at some distance from the Angelina 

 River, ha via g the same general course of the stream; or, if the lignitic series 

 was deposited continuously, the material was cut and carried away by erosion, 

 and a newer estuarine deposition, possibly lacustrine in part, took its place. 

 Apparently the newer deposition was afterward covered by drift of sandy 

 clay until again partly exposed by valley erosion. 



There are some facts which indicate that the calcareous greensand shell 

 marl was of more recent deposition than the Eocene strata. In the altered 

 greensand of the Siliceous Eocene — i. e. above the lignite bed and its associ- 

 ate series of siliceous limestone, clays, micaceous shales, etc. — the fossil shells 

 of Cardita planicosta, Turritella, sp. ind., etc., are without exception, so far as 

 the writer observed, only brown ferruginated casts in the orange loam, while 

 in the calcareous greensand shell marl of the oil regions along the valley of 

 the Bayou Visitador the white shells are themselves intact and tolerably well 

 preserved. The calcareous greensand shell marl was observed between ridges 

 only, while the altered siliceous greensand or orange formation (interior often 

 green) of the Eocene is coeval with the buff crumbly iron ore deposit. 



Near the office of the Lubricating Oil Company is an abundance of a bi- 

 valve shell of the Cardita type, but only about one-fourth the size of the 

 planicosta found in the Siliceous Eocene. The Ostrea sellceformis is also well 

 represented. The Turritella carinata exists mostly in fragments. The Astarte 

 Conradi and a shell resembling the Crassatella alia were tolerably well pre- 

 served. In the greensand shell marl at Simpson's Hill, four miles north- 

 west of Melrose, a section of which has been given, was found a scutella 

 similar if not identical with the Scutella subrotunda, Lam., which is recognized 

 in Europe as of the Miocene Tertiary. 



The writer is aware that these fossils have been figured and described as 

 belonging to the Claiborne group in the Gulf States, and have been assigned 

 to a place or horizon just above the lignitic series in the Eocene epoch, but 

 believes that after closer investigation they will be accepted as part of the 

 Miocene Tertiary. * 



