Pg. 8, 60-63, pl. 5. Copper Belle monzonite porphyry. Hand specimens of the monozonite porphyry differ greatly owing to diversity of metamorphism. Ranges from light-gray through buff to dark-greenish-gray, or even uniform pink; texture, however, remains remarkably constant in all varieties, being characterized by conspicuous phenocrysts of feldspar (1 to 10 mm in length). Groundmass everywhere clearly crystalline but aphanitic. Most exposed bedrock contacts are with Escabrosa limestone. All exposed contacts in Gleeson district are faults. Age is Triassic or Jurassic. Report includes geologic map.
Named from exposures on and near the Copper Belle claim, on west slope of Gleeson Ridge in Gleeson district, central Cochise Co., southeastern AZ. Outcrops form nearly complete elliptical ring on lower slopes of Gleeson Ridge. Smaller outcrops in alluvial areas to east and northeast, and considerable body exposed in Courtland district near and east of abandoned post office. Other smaller bodies exposed in the county.

Source: US geologic names lexicon (USGS Bull. 1200, p. 933).

Taken by Gilluly (1956) to be about same age as Gleeson Quartz Monzonite which has been radiometrically dated as Jurassic. Is in Pedregosa basin. Age assignment would be Jurassic rather than Triassic or Jurassic.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Has not been successfully dated because of intense alteration. Tentatively correlated with Piper Gulch Monzonite of the Santa Rita Mountains and Harris Ranch Monzonite of the Sierrita Mountains which have been dated as 184 m.y. old respectively, but may be a part of Gleeson Quartz Monzonite of Jurassic age. Correlation chart. Is in the Pedregosa basin. Previously considered Triassic or Jurassic age. Is of Triassic? age in this report.

Source: GNU records (USGS DDS-6; Denver GNULEX).