Terrigenous clastic and carbonate depositional systems comprising the upper half of the Strawn Group and the complete Canyon Group (Pennsylvanian) were deposited within the Forth Worth basin and on the Bend arch of north-central Texas. The stratigraphic interval involves 12 major format cycles of deltaic progradation and marine transgression. These units subdivide the outcrop and subsurface section into mappable genetic units. Variations in the rate of subsidence for the Fort Worth basin, Knox-Baylor trough, and Bend arch, as well as the initiation of subsidence to form the Midland basin, were responsible for the lithofacies geometry of individual depositional systems and gave rise to the "cyclothemic" cyclic sedimentation pattern. The effects of eustatic sea level change have not been recognized from facies-derived evidence in north-central Texas.

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Individual depositional systems have been identified and mapped using data from 4,100 well logs and 75 measured sections. For the upper Strawn (above the Brannon Bridge Limestone), subsurface isolith maps indicate the presence of four deltaic depocenters, one fan delta system, two carbonate banks, one carbonate platform, and an embayment-strand-plain complex during various stages of Desmoinesian and early Missourian deposition. Higher, within the Canyon Group, there are two deltaic depocenters, one fan delta complex, a clastic slope system, carbonate shelf-edge and shelf-interior banks, and a carbonate platform. On the basis of outcrop facies characteristics and net sandstone geometry, river-dominated and lobate deltas, as well as coarse-grained fan deltas, are the dominant clastic sy tems deposited on the Bend arch.

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