TERTIARY PERIOD. 509 



bluish marls, the former often indurated, with numerous shells, in Clarke co., 

 south of the preceding. Whole thickness, 425 feet. 



In Tennessee, there are, below, beds of sand (omjj^e-sand at surface, from 

 alteration of the oxyd of iron) with some clay, — the Porter's Creek group, 200- 

 300 feet thick; and over these layers, sand-beds containing Lignite, the La- 

 grange group, 300-400 feet thick, covering a large area in western Tennessee. 

 (Safford.) 



Near Charleston, S.C., (1) Buhrstone beds, 400 feet; (2) "White limestone and 

 marls, called the Santee beds. A Buhrstone of the same age occurs also in 

 Georgia and Alabama. The epoch is represented also near Fort Washington, 

 Piscataway, and Port Marlborough, in Maryland, and on the Pamunkey at 

 Marlbourne, mostly by dark-green sands. 



In the Upper Missouri region there is a great Lignite group, 2000 feet or 

 more thick, which contains much Lignite, numerous leaves of plants, and occa- 

 sionally in its lowest part shells of brackish-water Mollusks, as Oysters, Corbi- 

 cul?e, etc., mingled with fresh-water species, Vivijjarse, Melanise, etc. (figs. SOS- 

 SOS). It occurs about Fort Union, extends far north into British America, and 

 south to Fort Clarke; also on the North Platte, above Fort Laramie, on the 

 west side of Wind River Mountains, and into Green River Valley. (Meek & 

 Hayden.) 



A Lignite formation of Eocene age occurs also in Texas. (Shumard.) 



In California, the Claiborne epoch is represented at the Canada de las Uvas, 

 near the south extremity of the Tulare valley, where the Cardita planicosta, or 

 a species near it, occurs. 



The beds of the Jackson epoch, or Middle Eocene, as observed at Jackson, 

 Miss., are (1) Lignitic clay; (2) White and blue marls, the former often indu- 

 rated, with numerous marine shells and remains of the Zeuglodon. They cross 

 the State as a narrow band running E.S.E. through Scott and Jackson cos. 

 Whole thickness, 80 feet. (Hilgard.) 



The beds of the Vicksburg epoch, or Upper Eocene, as represented at Vicks- 

 burg, Miss., are (1) Lignitic clay, 20 feet; (2) Ferruginous rock of Red Bluff, 

 with numerous marine fossils, 12 feet; (3) Compact limestones and blue marls, 

 with marine fossils, often called the Orbitoides limestone, 80 feet: in all, 112 

 feet. A narrow band crosses the State just south of the Jackson beds, from 

 Vicksburg on the Mississippi. These are overlaid by 150 feet of the "Southern 

 Lignitic" or " Grand Gulf" group of clay, sandstone, and loose sand, with some 

 gypsum, occurring about Grand Gulf, on the Mississippi, and covering the 

 larger part of the southern portion of the State. (Hilgard.) 



The Vicksburg group is met with in Alabama, in Monroe, Clarke, and Wash- 

 ington cos., and constitutes a limestone bluff at St. Stephens on the Tombeckbee ; 

 limestone at Tampa Bay, Florida; gray marl on the Ashley and Cooper Rivers, 

 South Carolina, abounding in Rhizopods, and, along with the Santee beds, 

 having a thickness of 600 to 700 feet. 



In the Upper Missouri region, there are fresh-water beds 1000 feet thick, con- 

 sisting of white and drab clays with some layers of sandstone and local beds 

 of limestone, which are either of the Vicksburg or Yorktown epoch. They 

 occur in the Bad Lands (Mauvaises Terres) of White River (whence they have 

 been called the White River group by Meek & Hayden), on the Niobrara, and 



