Several outcrops, formerly quarried, occurring 5-6 km north- northwest of St. Jean are of a sill, probably varying from 2-7 m in thickness. Other outcrops along and to the east of the Richelieu River as far as 16 km to the north may be of the same sill. Currie (1976a, p. 66) reports that all the outcrops west of the river are of nepheline syenite whereas those to the east are of nepheline-kaersutite diorite.
CLARK, T.H. 1955. St. Jean-Beloeil area. Geological Report, Quebec Department of Mines, 66: 1-83.
CURRIE, K.L. 1976a. The alkaline rocks of Canada. Bulletin, Geological Survey of Canada, 239: 1-228.