144 
THE TERTIARY GEOLOGY OF THE 
3. 'I'lie fossilifcrous arenaceous deposit (Claibornian), best shown at Claiborne- 
subaqueous at St. Stephen’s— very rich in fossils, and of the age of the “ Calcaire 
Cirossier” of France. — 17 feet. 
2. “ Huhrstone ” (Sihceous Claiborne of Hilgard), comprising siliceoas clay-stones' 
(buhr-stone proper) densely charged with fossils or their impressions, laminated 
clays, sands and calcareous deposits — beds “5” and “c” of the Claiborne section, 
the cliff at White Bluff, and the so-called “ Chalk Hills ” of the southern part 
of the State. At Claiborne the representative beds consist of aluminous and 
calcareous deposits, poor in fossils, but containing occasional layers of Ostrea 
neVcpformis . — About 250 feet"? 
1. The Wood’s Bluff and Bashia (with Cave and Knight’s Branches) deposits (Eo- 
lignitic), consisting of alternating dark clays, greenish and buff sands, and 
numerous .seams of lignite, partly very rich in fossils, and as far as is yet posi- 
tively known, the oldest Tertiary deposits of the State. — 50 — 1 feet.* 
'I’he exact development of the Vicksburg (Oligocene) and Grand Gulf (Miocene ?) 
deposits, has not yet been determined. 
It apiK-ars very probable, from the investigations of Prof L. C. Johnson, that the 
limits of the Tertiary formation extend considerably farther to the north than have 
generally been represented on the maps, the northward extension at Allenton being 
ten miles, six at Camden, and seventeen at Butler Springs f 
Mississippi. 
'fhe Mississippi Tertiary formations, which cover by far the greater portion of the 
State, exhibit csscmtially three different facies: variously colored lignitiferous clays 
and sands— black, brown, blue, green, yellow, gray, and impure white; siliceous 
samistones and clay.stones containing marine fossils; and limestones and calcareous 
marls, also with marine fossils. Lignitic clays occur intercalated throughout almost 
t u on 1 1 rt .series of deposits, and conversely, small estuarine deposits of marine shells 
a-casmnally appear in the true lignitic strata.J All the subdivisions recognized in 
Alabama are also to be met with here, and as in that State, they follow each other in 
.u<Tc,s.on from north to south. The dip appears to he nearly conformable to 
l Cretaceons deposits, being tvostward- 
fnvcmeet'f northern part of the State, and southward— 10-12 
^ite) feet per m.le S. by W._i„ the southern part.§ 
iU cnm.Hj,oiiik.nt, Uopb not apttear to vl.’ f entnobly falls into this group, but its exact position, or 
anci IB consItleitMl by Win. holl to renrestwit f i ^ determined. It is seen to underlie the “Buhrstone,” 
IMair. Wileox Co., it is BtaU.l to regime ^tate. At Black’s 
we iiifonnod that, aecoitiinir to Tiiom.ax/*n ""^’Jacent Cretaceous limet-tone, but in a foot-note (p. 90), 
T«rti.r 7 . ^'haracterisfe fossil of this limestone, an is probably 
oi ociencc, new ser., xbii, p. 36, 1867. 
