from middle to late pennsylvanian, the ancestral rocky mountains, the northeast spur from colorado, (the uncompahgre uplift) became the source region for further continental river and stream deposits. rising sea levels and erosion led to the deposition of the wescogame formation, (grand canyon) by late pennsylvanian time, and in east utah, (paradox basin, southwest of uncompahgre uplift, the honaker trail formation); northeast of the uncompahgre uplift, the weber sandstone continued deposition.