THE RIVER AND THE ROCKS The Geologic Story of Great Falls and the Potomac River Gorge

Prepared under the auspices of the Geological Society of Washington from material provided by J. C. Reed, Jr., R. S. Sigafoos, and W. L. Newman of the U. S. Geological Survey, C. B. Hunt and G. W. Fisher of the Johns Hopkins University, and S. W. Schiffman, A. T. Outlaw, and S. Q. Smith of the National Park Service.

Drawings by J. R. Stacy of the Geological Survey; photographs on pages ii, 4, 10, and 14 by James Q. Reber of Bethesda, Md.

Botanical evidence of floods and flood-plain deposition, by Robert S. Sigafoos: U.S. Geological Survey Professional Paper 485—A, Washington, 1964, 35 p.

The geology of Howard and Montgomery Counties, by Ernst Cloos, C. A. Hopson, G. W. Fisher, and Emery T. Cleaves: Maryland Geological Survey, Baltimore, 1964, 373 p.

Crystalline rocks of the Potomac River Gorge near Washington, D. C., by John C. Reed, Jr. and Janice Jolly: U.S. Geological Survey Professional Paper 414—H, Washington, 1963.

The metamorphosed sedimentary rocks along the Potomac River near Washington, D. C., by George W. Fisher, p. 299-315, in Studies of Appalachian geology—central and southern: Wiley-Interscience Publishers, New York, 1970, 439 p.

Gold veins near Great Falls, Maryland, by John C. Reed, Jr. and John C. Reed: U.S. Geological Survey Bulletin 1286, Washington, 1970, 22 p.

The District of Columbia, its rocks and their geologic history, by Martha S. Carr: U.S. Geological Survey Bulletin 967, Washington, 1950, 59 p.

Geology and ground-water resources of Washington, D.C., and vicinity, by Paul M. Johnston, with a section on Chemical quality of the water by D. E. Weaver and Leonard Siu: U.S. Geological Survey Water-Supply Paper 1776, Washington, 1964, 97 p.