494 



CENOZOIC TIME. 





There is a Lignite deposit at Brandon, Vermont, associated with a bed of limonite 

 iron-ore, and abounding in fossil fruits, first described by E. Hitchcock. The plants^ 

 according to Lesquereux, are of the same period with those of the Mississippi, Tennes- 

 see and Arkansas Lower Lignite beds. 



2. Eocene Tertiary. — In the Rocky Mountains the subdivisions are as follows, 

 beginning below: (1) The Wahsatch group (Coryphodon beds of Marsh, see Plate XII.), 

 including the Vermilion Creek (5,000 feet thick) and Bitter Creek beds, and others in 

 New Mexico, which resemble the Laramie beds, but overlie them unconformably ; (2) 

 The Green River group, consisting of shales containing fossil fishes, plants, insects, but 

 no Mammals, and perhaps not newer than the Wahsatch; the Elko group is related to 

 it; (3) The Bridger group (Dinoceras beds of Marsh), in the Green River Basin, over- 

 lying the last, and abounding in remains of Mammals (with the Green River beds about 

 5,000 feet thick); (4) The Uinta group, to the south of the Uinta Range, 400 feet thick 

 (the Diplacadon beds of Marsh), occupying a small Eocene lake-basin in White River 

 Valley. 



The marine Eocene Tertiary of the Alabama Period. — The Clniboi ne beds at Claiborne, 

 Alabama, or the lower of the marine Eocene, consist, beginning below, of (1) Clay, 25 

 feet, overlaid by a bed of lignite, 4 feet; (2) Marl with Oysters (0. sellazformis Con.); 

 (3) Marly arenaceous limestone; (4) Marl with Oysters; (5) Sand with shells, partly 

 showing a beach origin, often called the "Orange-sand" group in the region. Whole 

 thickness, about 125 feet. 



In Mississippi, there are (1) the Siliceous Claiborne beds, sandstones and clayey 

 layers, near the middle of the western half of the State, 150 feet thick; (2) 60 feet of 

 martytes and limestone; (3) 80 feet of similar beds, best shown near Jackson, Missis- 

 sippi, and sometimes separated as the Jackson group; (4) 12 feet of Red Bluff beds, 

 black lignitic clays. Then follow 120 feet of beds of the Vicksburg series, or Upper 

 Eocene. (Hilgard.) 



The Claiborne beds are locally lignitic, a feature which increases westward in Arkan- 

 sas, but diminishes eastward in Alabama; and Hilgard considers it as proving that the 

 conditions under which the bottom lignitic beds (No. 1) were formed, continued on, in- 

 termittingly, into the following part of the Tertiary era. 



The beds at Jackson are (1) Lignitic clay; (2) White and blue marls, the former 

 often indurated, with numerous marine shells and remains of the Zeuglodon. They 

 cross the State as a narrow band, running east-southeast through Scott and Jackson 

 counties. Whole thickness, 80 feet. (Hilgard.) 



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

 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 "Grand Gulf" group of clay, sandstone, and loose sand, 

 with some gypsum, occurring about Grand Gulf, on the Mississippi, and elsewhere south 

 of the latitude of Jackson and Vicksburg, covering the larger part of the southern por- 

 tion of the State. (Hilgard.) 



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

 counties, and constitutes a limestone bluff at St. Stephens on the Tombigbee, and 

 limestone at Tampa Bay, Florida. 



Near Charleston, S. C, the oldest Eocene there displayed includes (1) Buhrstone 

 beds, 250 feet; (2) White limestone and marls, called the Santee beds. A buhrstone 

 of the same age occurs also in Georgia and Alabama; and the siliceous beds at Clai- 

 borne are of the same horizon. This group is represented also near Fort Washington, 

 Piscataway, and Fort Marlborough, in Maryland, and on the Pamunkey at Marlbourne, 

 mostly by dark green sands; and in New Jersey, at Squankum, etc. 



The Vicksburg epoch is represented in South Carolina by gray marl, on the Ashley 

 and Cooper rivers, abounding in Rhizopods; and, adding the Santee beds, the whole 

 thickness is 600 to 700 feet. 



Yorktown Period, or Miocene. — The Miocene beds cover a large part of the 



