The McCloud Limestone in northern California ranges from 100 to about 2,400 feet thick and is dominantly calcarenite with local concentrations of pisolite and limestone conglomerate. The limestone was deposited with graywacke, tuff, siltstone, and agglomerate in a eugeosynclinal environment. Field and petrographic studies indicate that the McCloud Limestone was deposited as a bank in relatively shallow, clear water, under vigorous local wave action. Deposition of the limestone terminated when the area was engulfed by pyroclastics, conglomerates and associated clastic debris. Diagenetic recrystallization included development of sparry calcite and grain-growth calcite.