Pg. 193. Dubuque formation. Irregular limestone and interlaminated carbonaceous shales, 10 feet thick at Dubuque, eastern Iowa, extending from "cap rock" below up to blue shales of Maquoketa member of Maquoketa series. Coincides with TRIPLICIA bed or zone, and forms basal part of Maquoketa series or stage. Overlain by Maquoketa formation proper and underlain by Galena formation. Age is Late Ordovician.
Named from Dubuque, Dubuque Co., eastern IA.

Source: US geologic names lexicon (USGS Bull. 896, p. 636-637).

Pg. 71-93. Dubuque limestone. Is basal Richmond, and older than Fernvale limestone [which to south underlies Maquoketa shale], and older than Maquoketa shale. In western Wisconsin and Iowa the Maquoketa overlies Dubuque formation where Dubuque is present. Age is Late Ordovician.
[See also under Volga shales.]

Source: US geologic names lexicon (USGS Bull. 896, p. 636-637).

Pg. 61, etc. Dubuque formation. Classify Dubuque as of Trenton age and include it in Galena group, as they call the Galena dolomite. On p. 27 Trowbridge stated Prosser, Stewartville, and Dubuque can be seen in Jo Daviess County, Illinois. Age is Late Ordovician.

Source: US geologic names lexicon (USGS Bull. 896, p. 636-637).

Dubuque formation of Richmond group. Adopted by the USGS. Present in eastern Iowa, southeastern Minnesota, southwestern Wisconsin, and northwestern Illinois. Age is Late Ordovician.
Named from Dubuque, Dubuque Co., IA.

Source: US geologic names lexicon (USGS Bull. 896, p. 636-637).

Pg. 90-92. Dubuque member of Maquoketa formation. Considered member of Maquoketa formation in Minnesota. Thickness about 30 feet. Underlies Wykoff member; overlies Stewartville member of Galena limestone.

Source: US geologic names lexicon (USGS Bull. 1200, p. 1168-1169).

Pg. 6, fig. 3. Dubuque formation of Galena group. In Dixon-Oregon area, northern Illinois, considered uppermost formation in Galena group. Thickness about 30 feet. Overlies Wise Lake formation (new).

Source: US geologic names lexicon (USGS Bull. 1200, p. 1168-1169).

Pg. 26, 297-299; A.V. Heyl, Jr., and others, 1959, USGS Prof. Paper 309, p. 17-18. Dubuque shaly member of Galena dolomite. Referred to as shaly member of Galena dolomite; overlies Stewartville massive member. In mining district member is light-gray to buff fine-grained sugary and silty dolomitic limestone that weathers to yellowish buff; medium- to thin-bedded and contains interbeds of platy dolomitic shale. Thickness 35 to 45 feet. Age of Galena is Middle Ordovician.

Source: US geologic names lexicon (USGS Bull. 1200, p. 1168-1169).

Pg. 1029 (fig. 1), 1040-1042, pl. 1. Dubuque formation. This report [Fillmore County, Minnesota] follows Kay's (1935, Jour. Geol., v. 43, no. 5) concept of type section. At type section, interval of transition from Stewartville rock to Dubuque rock is thicker than it commonly is in Minnesota. The Dubuque is unit of interbedded limestone and shale and contains two feldspathized shale beds. Control on thickness of Dubuque in southeastern Minnesota and adjacent Iowa is meager, but it is about 34 feet thick at two outcrops; in Fillmore County, outcrops are close to eroded edge of formation. Overlies Stewartville member of Galena formation; underlies Maquoketa formation. Age is upper Middle Ordovician.

Source: US geologic names lexicon (USGS Bull. 1200, p. 1168-1169).