LOWER CRETACEOUS. 601 



Section of portion of Trinity formation, 2^ miles west of southeast corner of Burnet quadrangle, at 

 south edge of quadrangle, from top of hill down to Cow CreeTc. 



'"> Feet. 



Soft sandy marl containing lamellibranchs 5 



Covered terrace 5 



Buff-weathering, massive, slightly honeycombed limestone containing fragments of shells 2J 



Sloping terrace of softer marly limestone 7J 



Steeply sloping surface underlain by nodular gray limestone with 2-inch laj-er of slightly gritty 



material 9 



Buff-weathering sandy limestone 6 



Light-buff calcareous shale, weathering nodular, containing some fossils 10 



Sandy calcareous limestone containing numerous fossils 5 



Sandy limestone 10 



Covered slope, probably underlain by soft bedded limestone 14 



Sandy limestone 1 



Soft, knotty, marly buff limestone 5 



Covered gentle slope 5 



Cream-colored limestone, slightly sandy 1 



Clayey marl; top 1 foot very fossiliferous; 5-inch band of buff limestone 2 feet from top 19 



Marly beds with hard layers containing some fossils 8J 



Yellow porous limestone containing shells 5J 



Similar, but more massive 6 



Similar, but thin bedded 5 



Similar, but shaly 14 



Solid yellow limestone 6 



Thin-bedded fossiliferous limestone 9 



Massive chalky limestone, with fossils 6 



Massive chalky limestone 15 



Shaly limestone, transition from above 8 



Fine-grained massive yellow limestone [ 7 



Calcareous shale 10 



Fine-grained gray sandstone, calcareous 5 



Covered slope 10 



Conglomerate with many pebbles 27^ 



Total in cliff and side of hill 247 



H-I 14. CENTRAL TEXAS. 



From Hill's detailed monographic discussion of the Cretaceous of Texas "^ are 

 taken the following extracts : 



Thestrataof the Lower Cretaceous, or Comanche series [in central Texas] * =f: * belong 

 to three divisions, as follows, beginning with the lowest : Trinity, Fredericksburg, and Washita. 

 The general characteristics of these divisions are as follows : 



The Trinity division is especially marked by strata of friable white packsands, which do 

 not occur in the other divisions and which in places constitute nearly the entire rocks of the 

 division. In some places, especially south of the Brazos, these sands alternate ■«-ith marly clays 

 and chalky and clastic limestones, the latter being composed of minute shells or fragmental 

 particles of shells and sands having a lithologic and paleontologic individuaUty by which they 

 can usually be readily distinguished. All the calcareous strata are white or yellowish and occur 

 in numerous persistent alterations of hard and soft strata of various thicknesses. 



The rocks of the Fredericksburg division in the typical area of occurrence are almost 

 entirely chalky limestone, initiated by beds of marly clay, which grade into the limestone. 



The rocks of the Washita division include the beds between the top of the Edv%'ards hme- 

 stone'of the Fredericksburg division and the coarse sands of the Woodbine (Dakota). 



The siediments of the Washita division, while generally light in color in their lower half, 

 show darker tones and greater ferrugination of rocks toward the top. They are composed 

 largely of alternations of marly clays and firmer layers of limest6ne. The limestones of this 



