B-02 Geology of the Grayback Mining District B-02 Geology of the Grayback Mining District, Costilla County, Colorado
MI-19 Nell’s Topographical and Township Map of the State of Colorado (detail) MI-19 Nell’s Topographical and Township Map of the State of Colorado
HM-01-04 1877 Geologic Map of Colorado (Hayden) (detail) HM-01A Six 1877 Geologic Map Sheets and Two Cross Sections of Colorado (Hayden)
HM-01-18 1877 Geologic Map HM-01-18 1877 Geologic Map, Sheet XVIII: Geologic Cross Sections of the Western Slope and Central CO (Hayden)
HM-01-17 1877 Geologic Map HM-01-17 1877 Geologic Map, Sheet XVII: Geologic Cross Sections of the Front Range and Central CO (Hayden)
HM-01-16 1877 Geologic Map HM-01-16 1877 Geologic Map, Sheet XVI: South-Central CO and Part of NM (Hayden)
HM-01-15 1877 Geologic Map HM-01-15 1877 Geologic Map, Sheet XV: SW CO and parts of NM, AZ and UT (Hayden)