The large northwest-trending graben-faulted anticline consisting of late Precambrian through Mississippian rocks exposed in the core of the San Juan Mountains near Silverton, Colorado, formed before Late Cambrian and was intermittently active into the Pennsylvanian. This structure may be considered an exposed segment of the southeastern Paradox basin and a reference to aid in understanding the basin. Sedimentation from Late Cambrian to Pennsylvanian and post-Pennsylvanian salt tectonics were all affected by the preliminary faulted structure. Pre-Pennsylvanian reservoir facies were best developed high on upthrown fault blocks. These are Late Devonian sand bars and Early Mississippian biogenic crinoid banks.