The area studied in this report is centred 30 kilometres north-east of Gander, Newfoundland. After an introduction on previous research and general geology of the study area, this report presents the results of 1986-87 mapping and subsequent research on the petrology, mineralogy, geochemistry, and geochronology of samples collected. It includes information on the distribution, lithology, petrography, and contact relationships of the rock units in the Gander River Complex, Davidsville Group, Gander Group, and non-stratified plutonic igneous rocks; geochemistry of the rock units; geochronologic age determinations using argon-argon and uranium-lead dating; sedimentological provenance of the Davidsville and Gander groups; geologic structure; metamorphic history; the paleotectonic and depositional setting; and potential economic deposits.