Identifier: annualreportofun2171geol (find matches)
Title: Annual report of the United States Geological Survey to the Secretary of the Interior
Year: 1880 (1880s)
Authors: Geological Survey (U.S.)
Subjects: Geological Survey (U.S.) Geology Water-supply Forest reserves Mines and mineral resources
Publisher: Washington : G.P.O.
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
ontologic characteristic. At Fort Worth, according toTalis section, there are 25 feet of sandy clay marl between the FortWorth limestone and the Gryplma washitaensis agglomerate. Thisrepresents the thickness of beds f, g, and h in the Fort Worth section,but has not been recognized south of that locality. i. (Horizon of Gryphsea washitaensis with O. carinata.) This is oneof the most persistent and conspicuous horizons in the Washita divi-sion. In the Denison section it consists of a number of well-definedflag-like layers of a shell agglomerate, made up almost wholly of G.washitaensis in which 0. carinata and 0. subovata occur occasionally.This agglomerate is persistent throughout the Washita division in thisrelative position as far south as the Colorado. At Fort Worth it maybe seen in the railway cuts in the southern part of the city. South ofthe Brazos it still persists, but is there included withthe Georgetown i Beds f, g, h, and i of this group correspond to the Denton marls of Taff
Text Appearing After Image:
1, Ammonites (Schloenbachia) leonensis Roemer; la, side view of 1 ; 2, Os*rea (Alectryonia) carinata Lamarck ; 3, Gryphaeawashitaensis Hill , 4, Epiaster elegans Shumard. Y HILL.) DENTON SUBGROUP. 273 formation, being still recognizable at Austin as a conspicuous horizoncomposed of the characteristic shell breccia, as may be seen in theSixth street cut of the International and Great Northern Railroad.Beds f, g, and h do not occur in the southern region. Distribution and occurrence.—The Denton beds are well-defined onlyin the region north of Trinity River. They crop out in the bluffs ofRed River from the upper end of Preston Bend, north of MartinSprings, in Gra)7son County, to Browns Ferry, in Cooke Count)^.West of the latter place the Fort Worth formation also appears in thebluffs. They also have considerable development in the opposite sideof Red River, in the Chickasaw Nation. At Browns Ferry, accordingto Mr. Taffs section, they have a thickness of 42 feet (see section No.30, p. 2

Note About Images