THE CANYON GROUP: A PRISTINE ASSEMBLAGE OF PENNSYLVANIAN TRACE-MAKING ACTIVITY IN RANGER, TEXAS, UNITED STATES

The Canyon Group is composed of genetically related terrigenous clastic facies and carbonates, exposed along a southwest to northeast band across North-Central Texas. Underneath a contact with the Ranger limestone, laminations of sandstone within the Placid shale member preserve a diverse assemblage of ichnofossils, including; Psammichnites isp., Arthrophycus isp., Gyrochorte isp., Thalassinoides isp., and other unassigned traces. The presence of these traces, along with associated unidirectional sedimentary structures, supports evidence that a deltaic depositional environment existed in this area during the Pennsylvanian. The lack of plant impressions suggests that this area may represent an intertidal deltaic shoal. The trace fossils present serve as much more reliable ecological diversity indicators than just body fossils alone, which are limited to fragmentary Nautiloids and a single damaged crinoid stem section.