0. IT. Gordon — Chalk Formations of Northeast Texas. 371 



Eagle Ford Formation. 



Blossom Sands. — Glauconitic sands interlaminated with and 

 grading into clay. Sands appear decidedly brown and red at 

 the surface from oxidation of the contained iron. Eighty 

 to one hundred feet thick. Constitute a narrow sandy belt 

 extending from east to west through Red River and Lamar 

 counties. Named from the village of Blossom in the eastern 

 part of Lamar county, which is located upon their outcrop. 

 Dark blue and black laminated clays with thinly bedded 

 clay limestone and nodular septaria of blue limestone. 

 These septaria are highly fossiliferoas and often weather 

 out in bowlders of various sizes. These clays grade down- 

 ward into the Woodbine sands and upward into the Blos- 

 som sands. Their thickness is from five hundred to six 

 hundred feet. 



Woodbine Formation. 



Ferruginous and argillaceous sands, in places glauconitic and 

 lignitiferous. Thickness estimated to be five hundred to eight 

 hundred feet. 



Steatigraphic Relations of the Annona Chalk. 



The chalk to which Hill gave the name Annona makes its 

 appearance on the south side of Red River in the northern 

 part of Red River county and extends in a belt 2 to 4 miles 

 wide to the south of west across Red River and Lamar coun- 

 ties, and westward. Owing to the hardness and greater resist- 

 ance to erosion, this belt appears usually as a low ridge, 

 covered to a slight depth only by soil through which the 

 white chalk frequently appears, and in which ribbons of white 

 mark the courses of wet-weather streams. The chalk con- 

 tains a varying proportion of sand. 



In composition, the chalk corresponds closely with that of 

 the Austin, as shown by the following analyses : 



l 



Calcium carbonate 84*14 



Silica and insolubles. 10-14 



Ferric oxide and alumina 4-04 



Magnesia (and H 2 0) 1'68 



1. Annona chalk, 7 miles south of Paris, Texas. Analysis fur- 



nished by Mr. J. A. Porter, Paris, Texas. 



2. Texas chalk, locality unknown. 21st Annual Report, U. S. 



Geological Survey,* Pt. VII, 1899-1900, p. 329. 



3. Rocky Comfort, Arkansas, Ibid. 



4. Average rock from quarry, Texas Portland Cement Works, 3 



miles west of Dallas, Texas, Ibid., p. 737. 



2 



3 



4 



82-51 



84-48 



70-21 



11-45 



9-77 



23-55 



3-61 



1-15 



1-50 



1-19 



trace 



0-58 



