Glen Rose Formation

Pg. 504, 507. Glen Rose or alternating beds. Soft yellow magnesium fossiliferous beds, siliceous at base, alternating with fine argillaceous sand with occassional dimension layers of almost pure crystalline limestones, chalk, and magnesium limestones, often oolitic in structure. Overlies Trinity or Basal sands and underlies Paluxy sands. [Age is Early Cretaceous (Comanche).] [Named from Glen Rose, Somervell Co., TX.] Glen Rose limestone. Middle formation of Trinity group. Underlies Paluxy sand and overlies Travis Peak sand (†Basal sands.) Age is Early Cretaceous (Comanche). Named from Glen Rose, Somervell Co., TX. Hazzard, R.T., 1939, Notes on the Comanche and pre-Comanche(?) Mesozoic formations of the Arkansas-Louisiana-Texas area and a suggested correlation with northern Mexico: Shreveport Geological Society Guidebook, June 2-4, 1939, no. 14, p. 155-189. Pg. 155-165. Glen Rose subgroup of Trinity group consists of Lower Glen Rose formation, Glen Rose anhydrite, and Upper Glen Rose formation. Lower Glen Rose indudes Pine Island member below and Rodessa member above. Overlies "Travis Peak" formation; underlies Paluxy formation. Subsurface data. [Age is Early Cretaceous.] Pg. 5, 8. Glen Rose limestone member of Shingle Hills formation. Rank reduced to member status in Shingle Hills formation (new). Overlies Hensell sand member. [Age is Early Cretaceous.] p. 67-78. Glen Rose limestone of Trinity group. At generalized reference section of Trinity division, Glen Rose limestone consists of lower unit and an upper unit. Lower subdivision, that is interval below CORBULA bed, is predominantly massive medium- to thick-bedded limestone with local mound-like concentrations of corals and caprinids in basal and upper parts. The lower Glen Rose above the massive limestone is largely shale alternating with thin-bedded limestones and is highly fossiliferous with several levels of ORBITULINA, the large Foraminifera used as a subsurface Glen Rose marker. Trinity section above CORBULA bed consists predominantly of buff-colored shales and fine-grained dolomites in lower and upper parts with darker shales and more resistant fossiliferous limestone in middle. The alternating relation of these lithic types resulted in early designation of "Alternating Beds" for the Glen Rose strata. Formal name was proposed by Hill (1891) from exposures near Glen Rose, Somervell County, Texas. Upper limit of Glen Rose in this area is placed at concordant contact of uppermost dolomitic section with overlying limestones similar to those higher in Fredericksburg division. Glen Rose is completely exposed from Hamilton Pool eastward to the Shingle Hills and has local thickness of 525 feet. Overlies Hensell sand. Lower Glen Rose contains basal coral reef at narrows of Blanco River. [Age is Early Cretaceous.] Pg. 2328-2363. Terms Glen Rose, Glen Rose undifferentiated, and Glen Rose subgroup, as used in this report [stratigraphy of Comanchean Cretaceous Trinity group], all refer to those rocks below top of Glen Rose as defined in Austin area and above top of either Pearsall formation or its equivalent. These terms are used in areas where the Ferry Lake is not recognizable. Undifferentiated Glen Rose time-stratigraphic unit is defined to include those rocks below isochronous surface contemporaneous with top of Glen Rose as defined in Austin area and above isochronous surface contemporaneous with base of Rodessa formation as defined in type area. Rusk formation (new) occupies stratigraphic interval formerly termed upper Glen Rose formation and Paluxy formation. Top of Trinity group, as term is used in present report, is defined as top of Glen Rose formation of the Austin area and its equivalents. Subsurface data. [Age is Early Cretaceous.] Winter, J.A., 1961, Stratigraphy of the Lower Cretaceous (subsurface) of south Texas: Gulf Coast Association of Geological Societies Transactions, v. 11, p. 15-24., See also Fredericksburg and Washita strata (subsurface Lower Cretace