EASTERN AND SOUTHERN UNITED STATES. 
141 
of Tuomey’s Bashia section * The basal lignite would then probably ba found to 
underlie the lowest stratum exhibited at the Bluff. Bed No. 6 (Wood’s Bluff section) 
can be traced down the river for a distance of two or three miles, when it dips beneath 
the water’s level. Somewhat below this point, and beyond the month of Witch Creek, 
the stratigraphical relation of the different beds is beautifully exhibited in a prominent 
cliff (“White Bluff”), rising from 250 to 275 feet above the river. The upper- 
portion of this bluff is constituted by the characteristic siliceous clay-stones and 
- silicified shell deposits of the southern “ Buhrstone ” formation, which make up fully 
100 feet of the vertical height. Laminated lignitic clays (bearing numerous leaf 
impressions), with occasional intercalated beds of pure lignite, enter mainly into the 
composition of the intermediate portion, i. e., from the water’s level to the base of the 
buhrstone above mentioned. Allowing a uniform southerly dip of 10 feet to the mile, 
which appears to be consistent with obtained data, it is manifest that at this point the 
lowest fossiliferous strata exposed at Wood’s Bluff (and consequently the equivalent 
deposits on Bashia Creek and its tributaries, Cave and Knight’s branches) must lie 
from 175 to 200 feet below the base of the siliceous mass constituting the true 
buhrstone ; or in other words, we have here a series of deposits aggregating about 300 
feet in thickness, which can be shown to be of an age anterior to the deposition of the 
Claiborne fossiliferous sands. At Baker’s Bluff, a few miles above St. Stephen’s 
(which is situated some twenty-eight miles south of Wood’s Bluff), the buhrstone, 
according to Tuomey, appears in a vertical escarpment rising only 50 feet above the 
water, a low height perfectly in accordance with the loss occasioned by the general 
dip extending over nearly twenty miles. At this point, moreover, occupjing a position 
above the buhrstone, Tuomey (o/j. cit., p. 148) identifies a bed of greensand, 8 feet in 
thickness, as the equivalent of the Claiborne fossiliferous sands (“ d ” of his section), 
and containing numerous fossils identical with tho^ e found at Claiborne. Still further 
south, and occupying a considerably lower level, the same bed is described as having 
a development of 12 feet, and immediately above St Stephen’s was seen to dip beneath 
the water’s edge. At this last locality we have a beautiful exhibit of what has 
generally been designated by the name of “ White Limestone. ”t 
There can be not the least doubt, however, that this “ White Limestone,” which 
has most frequently been taken to represent bodily the Vicksburg (Oligocene or “Or- 
bitoitic ”), is in reality, as has been long ago insisted upon by Winchell,:}: a combination 
of strata belonging to two distinct groups of deposits. The lower moiety, dipping 
into the river, and resting upon the subjacent Claiborne sand (Tuomey, op at., p. 157 ; 
Lyell, Q. Journ. Geol. Soc. Lond., iv, p. 15 ; Hale, A. J. Science, new ser., vi, p. 359), 
* The relations of the Bashia and Wood’s Blnff sections, as well as those of Cave and Knight’s branches, 
are fully set forth in my paper above referred to, Pros. A. N. S., 1880, pp. 364-70. 
f I have been unable to discover the exact height of this bluff. Neither Lyell nor Tuomey mentions it ; 
Conrad, in the appendix to Morton’s “Synopsis ” (p. 33), .states it is about 100 Let. 
I Proc. Amer. Assoc., 1856, part h, p. 85. 
19 JOUR. A. N. s. PHILA., VOL. IX. 
