EASTERN AND SOUTHERN UNITED STATES. 
145 
The following generalized section, slightly emended from Hilgard, is given upon 
the data furnished by that authority; the approximate thicknesses may be taken as 
minima, being often greatly exceeded. 
1. Grand Gulf Group, or southern Lignite (Miocene 1)— variously colored sandstones, 
with small lignite beds, tree-palms, exogenous trees, Arundinacece.— 150 feet. 
2. Vicksburg beds (Oligocene — “ Orbitoitic ”). 
a. CrystaUine limestones and blue marls, with Ostrea Vkksburgmsw, 0. gigan- 
tea, Pecten Poulsoni, Gardmm diversum, Area Mimssippiensis, Navimla 
Missmippiensis, N. lima, Grassaiella Missisdppiensis, Panopea oblongata, 
Fulgoraria Mississip^jiensis, Gtypreea lintea, Dentalium Mississippiemis, 
Madrepora Mississippiensis, Orhitoides ManteUi. — 80 feet. 
b. Ferruginous rock of Red Bluff (“ Red Bluff Group ” of Hilgard, typically 
exposed in the bluffs of Chickasawhay River, near Red Bluff Station, 
Wayne Co. — the correspondent of the “ Shell Bluff Group of Conrad 1), 
with Plagiostoma {Spondylus) dumosa, Gardita planicosta, G. rotunda, 
Rostellana velata, Fulgoraria Mississippiensis, Mitra Mississippiensis, 
Gassidaria lintea, Gonus sauridens, Busycon spiniger, Natica Vicksburgensis, 
Trochita trochiformis, Dtntalium thalloides, Osteodes, Madrepora, Flabellim 
Wailesii. — 12 feet. 
c. Lignitic clay and lignite, as shown at the base of Vicksburg bluff. 20 feet. 
3. Jackson beds (» Jacksonian ”= Bartonian). White (often indurate) and blue 
marls, underlaid by lignitic clay and lignite, with Zeuglodon macrospondylus, 
Gardita planicosta, Gardium Nicolleti, Leda multilineata, Gorbula bicarinata, 
Rostellaria velata, Oastridium vetustum, Morio Petersoni, Valuta dumosa, Mitra 
Millingtoni, M. dumosa, Gonus tortilis, Gyprma fenestralis, Trochita alta. 
Umbrella planulata, Flabellum Wailesii, Osteodes irroratus.—SO feet. 
4. Calcareous Claiborne (“ Claibornian ” — age of the “Calcaire Grossier”)- White 
(sometimes indurate) and blue marls, with the well-known Claiborne fossils. 
— 1 feet. 
5. Siliceous Claiborne (“ Buhrstone”— Suessonian in part) .^Sandstones and claystones 
with Claiborne fossils. — I feet. 
6. Lignitic or Northern Lignite (“ Eo-Lignitic ”)— Basal lignites, with mterstratified 
clays and sands, containing marine fossils, and (Tippah) plant remains— 
Garya, Populus, MorusF, Ficus, Laurus, Persea, Gornus, Olea, Rhamnus, 
Terminalia, Magnolia, Dryandroides ?, Rhus. — 425 — % feet. 
