1974. "General Geology", Geology of the Arisaig Area, Antigonish County, Nova Scotia, A. J. Boucot, J. F. Dewey, D. L. Dineley, R. Fletcher, W. K. Fyson, J. G. Griffin, C. F. Hickox, W. S. McKerrow, A. M. Ziegler
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Description of Formations
Browns Mountain Group
The chloritized graywackes, slates, argillites, and hematite beds of this group occur on the southeast side of the Hollow Fault and were not examined closely during the present study.
Williams (1914, p. 55) records the inarticulate brachiopod Obolus (Lingulobus) spissa from iron-ore beds and associated micaceous sandstones on the East Branch of Doctors Brook and north of the Little Hollow (which runs parallel to the Hollow three-quarters of a mile southeast of the West Branch of Doctors Brook). The same brachiopod occurs with the Arenig (Lower Ordovician) graptolite Didymograptus nitidus in the iron-ore beds of Belle Isle, Newfoundland (Williams, 1914, p. 55, footnote). The probability of an Ordovician age is strengthened by the fact that the Browns Mountain Group is intruded by monzonite stocks which do not intrude the Silurian, and further, because pebbles from these stocks occur in the Malignant Cove Formation; the Browns Mountain Group is therefore certainly pre-Silurian, and probably older than the Late Ordovician or lower Llandovery Bears Brook Volcanic Group.
Browns Mountain conglomerates, with pebbles up to 1 cm, grits, and sandstones occur high on the east bank of Doctors Brook above stations L17 and L21 (Pls. 5A, 5B); and basic tuffs and serpentine are exposed in the Hollow Fault zone along the East Branch of Doctors Brook (stations U88 to U94, Pl. 5C). Other outcrops noted include grits on the West Branch of Doctors Brook 8,000 ft upstream from the junction of the East and West Branches, and epidotized basic rocks on the East . . .