. Three distinct
rock types exist (Appendix A1 Table A1; Figs. 2–3): 1) a greenish-gray
to dark-greenish gray lithic arkose (Fig. 4a); 2) a dark grayish-black
silty shale/mudstone with coarser interlayers (Fig. 4b); and 3) a
brownish-red feldspathic arkosic sandstone