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—An Unjust Attack. 8 pp.—Am. Geol., Jan., 1889.

—The Philadelphia Meeting of the International Congress of Geologists. 10 pp., Am. Geol., June, 1890.

—Report of the Berlin International Geological Congress. 13 pp.—Am. Jour. Sci., XXX, December, 1885.

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—Report of the Sub-Committee of the Berlin Congress of Geologists on the Archæan. 80 pp.

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—Origin of the Lower Silurian Limonites of York and Adams Counties, 6 pp.—Am. Phil. Soc'y, March 19, 1875.