The Diligencia Formation in the Canyon Spring area consists of a 2,950-ft (800m) section of interbedded sedimentary and volcanic rocks that accumulated in an east-west-trending intermontane valley. Sedimentary facies are alluvial fan-braided fluvial, shoreline with interfingering basalt flows, fluvial-deltaic, and lacustrine. The alluvial fan-braided fluvial facies occurs in the basal part of the formation in the Canyon Spring area. Alluvial-fan processes predominated in the lower part of this facies where coarse debris was derived from an uplifted Precambrian schistose gneiss-augen gneiss basement complex on the south. Braided-fluvial processes predominated in the upper part of the facies where alternating sequences of sand and mudcracked mud accumulated.

Basin subsidence occurred with syntectonic outpourings of basalt. Some of the flows are pillow basalts that interfingered with rippled, well-sorted, fine-grained sand of the shoreline facies. Fossils are sparse in the shoreline facies and include ostracodes, land-mammal remains, and horizontal burrows. Spring-tufa deposits are present in a laterally persistent bed. As infilling of the lake occurred, deltas formed where gravel-bearing, sandy fluvial sediments of the fluvial-deltaic facies entered the lake. These deposits interfinger with the shoreline facies, and some of the boulders are anorthosite and Lowe-type granodiorite. Offshore, thin-bedded mud and silt of the lacustrine facies interfingered with the delta deposits. Evaporite lagoon conditions and volcanic activity (ash deposit ) were intermittent.

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