Detailed mapping of the bedding, cleavage, and lineation in the Sugarloaf Mountain area, Maryland, indicates the presence of an anticlinal dome. The structure, and consequent reversal of the stratigraphic sequence, and the lithologic similarity of the local quartzite and phyllites with those of known age 8 miles to the west indicate that the low-grade metamorphic rocks of this area are Lower Cambrian. It is hoped that this will shed light on the age of the highly crystalline metamorphics of the Maryland Piedmont. Some insight into the folding mechanism is afforded by the petrofabric study. The planes of liquid inclusion in quartz are apparently related to the ac cross jointing.