[61] Abstracts in this number are prepared by F. H. Knowlton, Henry B. Kummel, J. A. Bownocker. _ACKNOWLEDGMENTS._ The following papers have been donated to the library of the Geological Department of the University of Chicago: ABBOTT, CHARLES C., M.D. --Recent Archæological Explorations in the Valley of the Delaware. 30 pp., 1 pl.--Publications of the University of Pennsylvania. Series in Philology, Literature and Archæology, Vol. II, No. 1. ADAMS, FRANK D. --On Some Granites from British Columbia and the Adjacent Parts of Alaska and the Yukon District. 14 pp., Ill.--Canadian Record of Science, Sept. 1891. --Notes to Accompany a Tabulation of the Igneous Rocks based on the System of Professor H. Rosenbusch. 6 pp., 1 pl.--Canadian Record of Science, Dec. 1891. --On the Geology of the St. Clair Tunnel. 8 pp., 1 pl.--Trans. Roy. Soc. Canada, Section IV, 1891. --On the Presence of Chlorine in Scapolites. 5 pp.--Am. Jour. Science, Apr. 1879. --Notes on the Lithological Character of some of the Rocks Collected in the Yukon District and Adjacent Northern Portion of British Columbia. 6 pp.--Annual Report, Geol. Sur. of Canada, 1887. --On Some Canadian Rocks Containing Scapolite, with a Few Notes on Some Rocks Associated with the Apatite Deposits. 16 pp.--Canadian Record of Science, Oct. 1888. --On the Microscopical Character of the Ore of the Treadwell Mines, Alaska. 5 pp., Ill.--Read before the Royal Soc. Canada, May, 1889. --On a Melilite-Bearing Rock (Alnoite) from Ste. Anne de Bellevue, near Montreal, Canada. 10 pp., Ill.--Am. Jour. Sci., Vol. XLIII, Apr. 1892. AMI, HENRY M., M.A., F.G.S. --The Utica Terrane in Canada. 32 pp.--Canadian Record of Science, Oct. 1892. --Additional Notes on the Geology and Palæontology of Ottawa and its Environs. 11 pp.--Ottawa Naturalist, Sept. 1892. --Catalogue of Silurian Fossils from Arisaig, Nova Scotia. 7 pp.--From the Nova Scotian Inst. of Sci., Ser. 2, Vol. I, 1892. ANDREAE, A. --Ueber die Nachahmung verschiedener Geysirtypen und über Gasgeysire. 6 pp.--Gesammt-Sitzung vom 13 Jan. 1893. BAYLEY, W. S. --A Summary of Progress in Mineralogy and Petrography in 1892.--American Naturalist. BECKER, GEORGE F. --Finite Homogeneous Strain, Flow and Rupture of Rocks. 77 pp.--Bull. Geol. Soc. Am., Jan. 1893. BEECHER, C. E. --Notice of a New Lower Oriskany Fauna in Columbia Co., N. Y. 4 pp.--Am. Jour. Sci., Vol. XLIV, Nov. 1892. BRANNER, J. C. --Annual Reports of the Arkansas Geological Survey, 1888, Vols. 1, 2, 3, 4; 1889, Vol. 2; 1890, Vols. 2 and 3. BRYCE, GEORGE, LL.D. --Older Geology of the Red River and Assiniboine Valleys with an Appendix. 7 pp., Ill. Read before the Historical and Scientific Society of Manitoba, Nov. 1891. BROADHEAD, G. C.