372 THE CHICAGO ACADEMY OF SCIENCES. 



Cooper, Amer. Nat., Ill, p. 397, 1869.— Dall, Proc. Bos. Soc. X. H., XIII, p. 



248, 1870.— Gould, Ed. Binney, p. 478, fig. 729, 1870.— Froebel, Proc. Lye. X. II., 



I, p. 72, 1870.— PVerrell & Smith, Amer. Journ. Sci., II, p. 44s, 1871.— Hay- 

 den, Prelim. Rep. U. S. Geol. Surv. Wyoming, p. 170, 1871. — Tryon, Con. Hald. 

 Mon., p. 104 (78), 1872.— Carpenter, Smith. Mis. Coll., X, pp. 93, 116, 1872.— 

 Byrnes, List. Sh. Cin., p. 2, 1872. — Jeffrey's, Ann. Mag. X. II., Ser. 4, X, p. 

 247, 1872.— Tryon, Proc. Phil. Acad., 1873, p. 286; Journ. Conch., I, p. 16, 

 1874. — Calkins, Cin. Quart. Journ. Sci., I, p. 323, 1874; Proc. Ottawa Acad. 

 Sci., 1874, p. 25.— Smith, Rep. U. S. Fish. Com., 1874, p. 702.— Yarrow, U. S. 

 Geog. Surv. West 100th Merid., V, p. 944, 1875.— Gilbert, U. S. Geol. Surv. 

 West 100th Merid., Ill, pp. 99, 100, 1875.— Walker & Beecher, Proc. Ann. 

 Arb. Sci. Asso., p. 45, 1876.— Pop. Sci. Mon., X, p. 248, 1876.— Bland & Cooper, 

 Ann. N. Y. Lye. N. H., VII, p. 370, 1876.— Ingersoll, Proc. Daven. Acad. Sci., 



II, p. 132, 1877.— King, U. S. Geol. Surv. 40th Parallel, I, p. 494, 1878.— Witter, 

 Journ. Conch., I, p. 386, 1878.— Walker, Journ. Conch., II, p. 330, 1879.— Stein, 

 Ind. Dept. Stat. & Geol., 1880, p. 458.— Heron, Ottawa Naturalist, I, p. 39, 1880.— 

 Home & Science Gossip, 1881. — Ottawa Nat., II, p. 263, 1885. — Christy, Journ. 

 Conch., IV, pp. 3, 47, 1885.— Sampson, Bull. Sedalia N. H. Soc, No. 1, p. 24, 

 1885.— Beauchamp, Land and F. W. Sh. N. Y., p. 3, 1886.— Sterki, Xach. Mall. 

 Ges., XVIII, p. 19, 1886.— Keyes, Bull. Essex Inst., XX, p. 71, 1888.— Web- 

 ster, Amer. Nat. XXII, p. 419, 1888.— H. F. Cpr., Cat. Sh. R. I., p. 5, 1889 — 

 Marsh, Conch. Exch., II, p. 103, 1888.— Ckll., Journ. Conch., VI, p. 64, 1889.— 

 Ottawa Nat., IV, p. 56, 1890.— Shimek, Bull. Lab. N. H., Univ. Iowa. I, p. 68, 

 1890.— Sterki, An. Rep. Geol. Surv. Tex., Ill, pp. 263, 265, 1891.— Walton, 

 Proc. Roch. Acad. Sci., II, p. 12, pi. 6, figs. 7, 8, 1891.— McGee, Rep. U. S. 

 Geol. Surv., XL, p. 461, 1891.— Walker, Nautilus, VI, p. 34, 1892.— Taylor, 

 Ottawa Nat., VI, p. 35, 1892.— Dean, Amer. Nat., XXVI, p. 11, 1892.— Mar- 

 shall, Rep. N. Y. State Mus., XLVII, p. 64, 1893.— Singley, An. Rep. Geol. 

 Surv. Texas, IV, p. 313, 1893.— Walker, Rev. Fauna Mich., p. 17, 1894.— Sar- 

 gent, Nautilus, VII, p. 121, 1894.— Stupakoff, Nautilus, VII, p. 135, 1894 — 

 Marshall, Rep. N. Y. World's Fair, p. 511, 1894.— Pilsbry, Proc. Phil. Acad., 

 1894, p. 23— Nylander, VIII, p. 125, 1895.— Whiteaves, Ottawa Nat., IX. p. 

 22, 1895.— Shick, Nautilus, VIII, p. 138, 1895.— Walker, Nautilus, IX, p. 5, 

 1895.— Taylor, Ottawa Nat., IX, pp. 175, 176, 1895.— Marshall, Rep. X. Y. 

 State Mus., XLVIII, p. 642, 1895.— Ward, Bull. Mich. Fish. Com., No. 5, p. 65, 

 1895.— Snyder, The Museum, III, p. 12, 1896.— Pilsbry, Proc. Phil. Acad., 1896, 

 p. 493. — Dana, Man. Geology, p. 966, 1896. — Hershey, Amer. Journ. Sci., iv, 

 IV, p. 96, 1867.— Ami, Ottawa Nat., XI, p. 26, 1897.— Dall, Proc. Xat. Mus.. 

 XIX, p. 368, 1897.— Nylander, Nautilus, XI, p. 10, 1897.— Shimek, Proc. Iowa 

 Acad. Sci., V, pp. 35, 44, 1897.— Baker, Journ. Cin. Soc. N. H., XIX, p. 78, 

 1897; Nautilus, XII, p. 65, 1898.— Walker, Nautilus, XI, p. 122, 1898.— Walton, 

 The Museum, IV, P- 133, 1898.— Baker, Trans.. Acad. Sci. St. Louis, VII, p. 89, 

 1898. — Pilsbry, Amer. Journal Sci., iv, V, p. 233, 1898. — Pilsbry, Nautilus, XIII, p. 

 65, 1899.— Baker, Nautilus, XIII, p. 30, 1899.— Smith, Nautilus, XIII, p. 35, 

 1899.— Baker, Nautilus, XIII, p. 58, 1899.— Hanham, Nautilus, XIII. p. 6, 1899. 

 —Sterki, An. Rep. Ohio State Acad. Sci., VIII, p. 34, 1900.— Pilsbry, Proc. 

 Phil. Acad., 1900, p. 457.— Walker, Geol. Surv. Mich., VII, pt. 2, p. 251, 1900.— 

 Nylander, Nautilus, XIII, p. 104, 1900.— Baker, Journ. Cin. Soc. N. H., XIX, 

 p. 176, 1900.— Stearns, Proc. Nat. Mus., XXII, p. 136, 1900.— Letson, Bull. Buff. 



