Disotopic dating of zircons from the Flat River Complex in the Carolina "slate" belt north of Durham, N.C. shows this intrusive complex to be 650 ± m.y. old. Modal analyses of granophyric groundmass compared to experimental data, the presence of vent breccias and related pyroclastic deposits, and consideration of age relations between the intrusive and extrusive rocks indicate that the Flat River was emplaced at very shallow levels (< l km) and acted as the source for most of the volcanic material surrounding the complex. The age determined for the Flat River Complex indicates that deposition of the volcanic rocks began prior to 650 m.y. ago and extends the slate belt volcanicity interval to 130 m.y. (520 to 650 m.y. b.p.) Both subareal and marine depositional environments are represented in the stratigraphic sequence. / Master of Science