Weno and Pawpaw Formation? 33 



The transitional zone from the ironstone to the clay facies occurs in Den- 

 ton and northern Tarrant Counties. As far south as the Trinity River con- 

 siderable amounts of ironstone fragments occur in the Pawpaw exposures ; 

 these are the residue of numerous thin ironstone ledges similar to those of 

 the Red River area but sparsely fossiliferous, which are scattered rather 

 evenly throughout the formation. The interbedding material is an arena- 

 ceous clay. South of the Trinity the section is prevailingly clay but has 

 thin ironstone, limestone and sand seams. 



SECTION OF THE PAWPAW FORMATION AT BLUE MOUND ONE AND ONE- 

 HALF MILES SOUTH OF HASLET, TARRANT COUNTY, TEXAS 



MAINSTREET: Feet 



White chalky limestone, exposed 4 



PAWPAW: 



Brown to yellow, sparsely fossiliferous clay, with thin ironstone seams and 



scattered sand lenses 23 



Sandstone flag layer 0.3 



Brownish yellow impure clay 4 



Thickness of Pawpaw 27 . 3 



On Sycamore Creek, three miles southeast of Fort Worth the Pawpaw has an average 

 thickness from several measurements of 7.5 meters (24.6 feet). 



At the southern border of Tarrant County the Pawpaw 'is 12 feet thick 

 and is transitional to the marl facies. In northern Johnson County the 

 transitional zone continues and the section consists of clay mixed with 

 marl. Passing from the upper Noland's River southeast to Riovista the 

 section changes considerably, for from Riovista southward the marl facies 

 is found, with little clay and no ironstone; there is also a corresponding 

 change in the Pawpaw fauna. 



SECTION OF BRANCH OF NOLAND'S RIVER NEAR CLEBURNE-WEATHER- 



FORD ROAD, 10 MILES WEST OF CLEBURNE, TEXAS 



Section furnished by W. M. Winton 



MAINSTREET: Feet 



Massive limestone containing Pachymya sp., Turrilites brazoensis, Holectypus 



limitis, Pecten sp 32 . 4 



PAWPAW: 



Reddish clay containing fragments of Turrilites sp., Area sp., etc.. pyritized 10.8 



WENO: 



Limy marl capped by a hard lime ledge one foot thick, containing Pecten 



georgetownensis, Nautilus texanus, Pinna sp., Kingena sp 7.8 



