OF NORTH AMERICA. 261 



XXI, p. 83, 1887. CKLL., Ann. Mag. N. H., ser. 5, XIX, p. 176, 1887. SHIMEK, 

 Amer. Geol., I, p. 151, 1888; Bull. Lab. N. H., Univ. Iowa, I, p. 69, 1888; Bull. 

 Lab. N. H. Univ. Iowa, I, p. 209, 1888. HOLZINGER, Rep. Nat. Hist. Surv. Minn., 

 XVI, p. 490, 1888. CPR., Cat. Moll. R. I., Ed. 2, p. 5, 1889. SHIMEK, Bull. Lab. 

 N. H. Univ. Iowa, I, pp. 209-212, 1890. Ottawa Nat., IV, p. 56, 1890. WOOD, 

 Nautilus, V, p. 56, 1891. SAMPSON, Ann. Rep. Geol. Surv. Ark., II, p. 193, 

 1891. Fox, Nautilus, IV, p. 114, 1891. McGEE, Rep. U. S. Geol. Surv., XI, pp. 

 461, 471, 1891. PLEAS, Nautilus, IV, p. 131, 1891. TAYLOR, Ottawa Nat., VI, 

 p. 35, 1892. SINGLEY, Rep. Geol. Surv. Texas, IV, p. 188, 1892; p. 313, 1893. 

 DEAN, Amer. Nat., XXVI, p. 18, 1892. WALKER, Nautilus, VI, p. 34, 1892. 

 MARSHALL, Rep. N. Y. State Mus., XLVII, p. 65, 1893. VAUGHAN, Amer. Nat., 



XXVII, p. 944, 1893. SAMPSON, Nautilus, VII, p. 33, 1893. STEARNS, N. Am. 

 Fauna, VII, p. 275, 1893. PILSBRY, Proc. Phil. Acad., 1894, p. 24. SQUYER, 

 Nautilus, VIII, p. 65, 1894. STUPAKOFF, Nautilus, VII, p. 135, 1894. WALKER, 

 Rev. Mol. Mich., p. 17, 1894. MARSHALL, Rep. N. Y. World's Fair, p. 512, 1894; 

 Rep. N. Y. State Mus., XLVIII, p. 642, '1895. SHICK, Nautilus, VIII, p. 138, 

 1895. HARPER, Journ. Cm. Soc. N. H., XVIII, p. 95, 1895. WHITEAVES, Ottawa 

 Nat., IX, p. 22, 1895. SARGENT, Nautilus, IX, p. 127, 1896. DANA, Geology, p. 

 966, 1896. PILSBRY and RHOADS, Proc. Phil. Acad., 1896, p. 493. UDDEN, Proc. 

 Iowa Acad., V, p. 103, 1897. BAKER, Nautilus, XI, p. 30, 1897. WISWALL, Nat. 

 Sci. Journ., I, p. 47, 1897. SHIMEK, Proc. Iowa Acad. Sci., V, pp. 35, 44, 1897. 

 HERSHEY, Amer. Journ. Sci., iv, IV, p. 96, 1897. PILSBRY, Amer. Journ. Sci., 

 iv, V, p. 233, 1898. TODD, Proc. Iowa Acad., VI, p. 127, 1898. BAKER, Trans. 

 Acad. Sci. St. Louis, VIII, p. 89, 1898; Nautilus, XII, p. 65, 1898. WALKER, 

 Nautilus, XI, p. 122, 1898. BEYER, Proc. Iowa Acad., VI, p. 118, 1898. PILS- 

 BRY, Nautilus, XIII, p. 65, 1899; Nautilus, XIII, p. 79, 1899. SMITH, Nautilus, 

 XIII, p. 35, 1899. BAKER, Nautilus, XIII, p. 30, 1899. HANHAM, Nautilus, XIII, 

 p. 6, 1899. LEVERETT, Mon. U. S. Geol. Surv., XXXVIII, pp. 169, 170, 171, 172, 

 1899. TODD, Proc. Iowa Acad. Sci., VI, p. 127, 1899. STERKI, An. Rep. Ohio 

 State Acad. Sci., VIII, p. 34, 1900. -PILSBRY, Nautilus, XIV, p. 10, 1900. PRICE, 

 Nautilus, XIV, p. 76, 1900. PILS. & COCK., Nautilus, XIV, p. 86, 1900. STEARNS, 

 Nautilus, XIII, p. 101, 1900; Nautilus, XIII, p. 132, 1900. SHIMEK, Amer. Geol., 



XXVIII, p. 354, 1901; Geol. Surv. Iowa, p. 264, 1901; Bull. Lab. N. H. Univ. 

 Iowa, V, p. 208, 1901. STEARNS, Proc. Nat. Mus., XXIV, p. 288, 1901. BAKER, 

 Trans. Acad. Sci. St. Louis, XI, p. 9, pi. 1, fig. 14, 1901. STERKI, An. Rep. Geol. 

 Surv. Tex., Ill, p. 263, 1901. DANIELS, An. Rep. Dept. Geol. Nat. Res. Ind., 

 XXVII, p. 637, 1902. ELROD., Bull. Univ. Mont. Biol, ser. No. 3, p. 172, 1902. 

 BAKER, Moll. Chi. Area, p. 268, pi. 30, fig. 21, text fig. 86, 1902. SHIMEK, Geol. 

 Surv. Iowa, 1902, pp. 171, 172. WALKER, Geol. Surv. Mich., VIII, pt. 3, p. 101, 

 1903. BAKER, Nautilus, XVII, p. 39, 1903. FULLER & CLAPP, Bull. Geol. Soc. 

 Amer., XIV, p. 162, 1903. SHIMEK, Bull. Lab. N. H. Univ. Iowa, V, p. 379, 1904. 

 BAKER, Nautilus, XVII, p. 113, 1904. KEEP, West. Amer. Sh., p. 314, 1904. 

 BAKER, Trans. Acad. Sci. St. Louis, XIV, p. 103, 1904. LETSON, Bull. N. Y. State 

 Mus., LXXXVIII, p. 56, 1905. CHADWICK, Bull. Wis. Nat. Hist. Soc., n. s., iv, p. 

 82, 1906 ; Nautilus, XX, p. 22, 1906. WHEAT, Bull. Brook. Conch. Club., I, p. 10, 

 1907. LETSON, Bull. Buf. Soc. Nat. Sci., IX, p. 242, 1909. 



Limnea humilis DEKAY, Zool. N. Y., p. 71, pi. 4, figs. 71, a. b., 1843. 

 MIGHELS, Bost. Journ. N. H., IV, p. 336, 1843. HALDEMAN, Rupp's Hist. Lane. 

 Co., p. 480, 1844. ANTHONY, L. & F.-W. Sh. Cin., 1848. GOULD, Agassiz's Lake 



