Pg. 42 and passim. White Ridge limestone member of Jefferson formation. Basal member of Jefferson limestone. Rests unconformably on Devils Glen dolomite (Cambrian) and underlies Glenn Creek shale member of Jefferson limestone. Thickest (150 feet) on Gordon Mountain; thinnest (50 feet) on Spotted Mountain. Has no one distinguishing characteristic, but varies considerably in composition at different places, being buff shaly arenaceous limestone on Pentagon Mountain, Monitor Mountain, and Wall Creek-Juliet Creek Ridge; changing until it is massive white-gray sandy siliceous limestone on Nannie Basin Ridge, Gordon Mountain, and Spotted Bear Mountain. Named for White Ridge. Forms lower part of slope above saddle on south side of peak forming west end of White Ridge, in S/2 sec. 16, T. 22 N., R. 11 W., [Slategoat Mountain 7.5-min quadrangle, 1995 ed., Lewis and Clark Co., northwestern MT]. On White Ridge it is 63 feet thick and consists of 39 feet of massive brown thin-bedded argillaceous fine-grained limestone that weathers to shaly light gray-buff fragments; underlain by 24 feet of thin-bedded steel-gray calcareous sandstone that weathers drab, gray-buff. Age is Middle Devonian.

Source: US geologic names lexicon (USGS Bull. 896, p. 2324).

Pg. 15, 49, 50. White Ridge limestone member of Jefferson limestone. Basal Devonian.

Source: US geologic names lexicon (USGS Bull. 1200, p. 4212-4213).