Although one of the Monteregian intrusions, Rougemont contains few alkaline rocks. The main mass comprises feldspathic peridotite, although G.N. Eby (personal communication, 1984) says that this area consists essentialy of pyroxenite and gabbro, and areas of layered and hornblende gabbros. Dykes are relatively abundant within the intrusion and collar of hornfelses. There are olivine-pyroxene-phyric dykes confined to the hornfelses, fine- grained non-porphyritic gabbros and camptonites with ocelli (Philpotts, 1976, p. 1154) for which trace element data of ocelli and matrix have been determined (Eby, 1980).
CURRIE, K.L. 1976a. The alkaline rocks of Canada. Bulletin, Geological Survey of Canada, 239: 1-228.
EBY, G.N. 1980. Minor and trace element partitioning between immiscible ocelli-matrix pairs from lamprophyre dikes and sills, Monteregian Hills petrographic province, Quebec. Contributions to Mineralogy and Petrology, 75: 269-78.
EBY, G.N. 1984b. Geochronology of the Monteregian Hills alkaline igneous province, Quebec. Geology, 12: 468-70.
PHILPOTTS, A.R. 1972. Monteregian Hills: Mounts Johnson and Rougemont. 24th International Geological Congress, Canada, Excursion Guide, B-14: 1-17.
PHILPOTTS, A.R. 1976. Silicate liquid immiscibility: its probable extent and petrogenetic significance. American Journal of Science, 276: 1147-77.