CENOZoic (marine). 275 
in the latitude of Jackson can be settled by the existence of a fault 
or fold, although the latter is a welcome suggestion with respect 
to the unaccountable irregularity between Canton and Byram. 
The absence of rise in any wells bored in the Grand Gulf beds 
anywhere, while rise occurs in all the borings in the marine beds, 
seems to indicate some sudden break after all. I have nowhere 
been able to find a sufficiently long exposure in the direction of 
the dip to trace unconformity on the contact between Grand Gulf 
sandstone and the lignito-gypseous beds overlying the orbitoides 
rock." 
By way of comparison and as a summary of what we have 
been able to determine as regards the distribution of the Eocene 
strata in the Atlantic and Gulf regions of the United States, the 
following is submitted: 
Lignitio. — The beds of this division appear to have their 
maximum development in Alabama in the vicinity of the Ala- 
bama and Tombigbee rivers, where they consist of sands and 
clays usually strongly glauconitic, holding beds of lignite, and 
interst ratified with several distinctively marine beds with charac- 
teristic fossils. Towards the east the marine beds become more 
prominent almost to the exclusion of the lignitic feature, but 
beyond Georgia, or even for any considerable distance into 
Georgia, this division has not yet been certainly identified, 
although a part of the Maryland Tertiary beds appear to belong 
here. 
Towards the west and northwest, the lignitic feature is retained, 
but the beds which can certainly be identified as belonging to this 
division appear to be thinner in Mississippi and Tennessee than 
in the type localities. The difficulty in identification is chiefly 
due to the comparatively insignificant development of the marine 
beds, and to the fact that the other overlying divisions of the 
Eocene in these States assume a lignitic character. Thus both 
the Claiborne and Vicksburg in Mississippi are much more de- 
cidedly lignitic than in Alabama. Beyond the Mississippi we 
are still less able to distinguish between the true Lignitic and the 
lignitic phases of the other divisions. 
Buhrstone. — This division has been identified in South Caro- 
lina, Alabama, and Mississippi, with practically the same features 
in each State. Beyond the Mississippi we have no certain notes 
of its occurrence. 
