A CKNO J VLED C ME NTS. 1 1 I 



— Contributions to Mineralogy, No. 54 ; (with Crystallographic Notes by S. L. 

 Penfield. 9 pp. — Am. Jour. Sci., Nov., 1892. 



— On Penfieldite, a new species, i pp. — Am. Jour. Sci., Sept., 1892. 



— Mineralogisclre Mittlieilungen, by F. A. Qentli (with Crystallographic Notes 

 by S. L. Penfield). 10 pp. 111.—" Zeit. fur Krystallog." XVIII, 6, (1891). 



— Examination of the North Carolina Uranium Minerals. 7 pp. — Am. Chem. 

 Jour. Vol. I, Nos. 2 and 3. 



— On some American Vanadium Minerals. 6 pp.— Am. -Jour. Sci., July, 1876. 



— On an undescribed Meteoric Iron from East Tennessee. 4 pp., 2 pi. — Proc. 

 Acad. Nat. Sci. Phila., Dec. 28, 1886. 



— Lansfordit, ein neues Mineral, 2 pp. 



— On the Vanadates and lodyrite, from Lake Valley, Sierra Co., New Mexico. 

 13 pp. Read before Am. Phil. Soc'y Apr. 17, 1885. 



— Contributions to Mineralogy. — Am. Jour. Sci., Sept. 1859 ; March, 1862, 

 May, 1868. 



— Meteorology. 6 pp. 



— Meteorology. 4 pp. — Am. Jour. Sci., Nov., 1861. 



— Re-examination of the Tetradymite from Field's Gold Mine, Georgia. 



— On Pyrophyllite from Schuylkill Co., Penn. Read before Am. Phil. Soc'y, 

 July 18, 1878. 



— Mineralogische Mittheilungen. 31 pp., 2 pi. — Zeit. fur Krystallographie, 

 1885. 



— ^Jarosite from Utah, i p. — Am. Jour. Sci., Jan., 1890. 



— On Two Minerals from Delaware Co., Pa. 3 pp. — Proc. Acad. Sci. of 

 Phila., 1889. 



— Contributions from the Laboratory of the University of Pennsylvania. 

 -Gilbert, G. K. 



— The Colorado Plateau Region considered as a Field for Geological Study. 

 27 pp. — Am. Jour. Sci., July and August, 1876. 



— The Strength of the Earth's Crust. 5 pp. — Bull. Geol. Soc. Am. Vol. 

 I, 1889. 



— The History of the Niagara River. 24 pp., 8 pi. — Sixth An. Rept. of Com. 

 of State Reservation at Niagara, 1889. 



— The Work of the International Congress of Geologists. 22 pp. — Am. Jour. 

 Sci., Dec, 1887. 



— The Sufficiency of Terrestial Rotation for the Deflection of Streams. 6 pp. — 

 Nat. Acad. Sci., 1884. 

 Gordon, C. H. 



— Observations on the Keokuk Species of Agaricocrinus. 7 pp., i pi. — Am. 

 Geol., May, 1890. 



— On the Brecciated Character of the St. Louis Limestone. 9 pp., 2 pi. — Am. 

 Nat., April, 1890. 



— Proceedings of the Iowa Academy of Sciences for 1887, 1889, 1889. loi pp. 



— Quarternary Geology of Keokuk, Iowa, with Notes on the Underlying Rock 

 Structure. 8 pp., 2 pi. 

 Grant Uly. S. 



— Notes on the Molluscan Fauna of Minnesota. 4 pp. — i6th An. Rept. Geol. 

 and Nat. Hist. Survey, Minn. (1887). 



— Account of a Deserted Gorge of the Mississippi near Minnehaha Falls. 

 6 pp., I pi. 



— Conchological Notes. 12 pp. — 14th An. Rept. Geol. and Nat. Hist. Survey, 

 Minn. 



— The Stratigraphical Position of the Ogishke Conglomerate of Northeastern 

 Minnesota. 8 pp. — Am. Geol. Vol. X, July, 1892. 



— Report of Geological Observations made in Northeastern Minnesota during 

 the Summer of 1888. 67 pp. — Geol. and Nat. Hist. Survey of Minn.; part IV. 

 17th An. Rept. 

 Hall, C. W. 



— Notes on a Geological Excursion into Central Wisconsin. i8 pp., i pi. 



