978 BULLETIN 92, UNITED STATES NATIONAL MUSEUM. 



Pianodema subaequata (Conrad). 



Orthis subaaquata Conrad, Proc. Acad. Nat. Sci. Philadelphia, 1, 1843, p. 333. 

 Hall, Pal. New York, 1, 1847, p. 118, pi. 32, fig. 2; Geol. Wisconsin, 1, 1862, 

 p. 42, figs. 1-3, and p. 436; 2d Ann. Rep. New York State Geol., 1883, pi. 34, 

 figs. 19-24. Emmons, Amer. Geology, 1, pt. 2, 1855, p. 194, pi. 9, f. 2. 

 Lesley, Geol. Surv. Pennsylvania, Rep. P 4, 1889, p. 533, figs. 



Orthis minneapolis N. H. Winchell, 8th Ann. Rep. Geol. Nat. Hist. Surv. Minne- 

 sota, 1880, p. 63. 



Orthis perveta Hall, 2d Ann. Rep. New York State Geol., 1883, pi. 34, figs. 17, 

 18 (?16). 



Dalmanella subaequata Hall and Clarke, Pal. New York, 8, pt. 1, 1892, pp. 194, 

 207, 224, pi. 5C, figs. 6-11. Weller, Geol. Surv. New Jersey, Pal., 3, 1903, 

 p. 156, pi. 10, figs. 3, 4. Grabau and Shimer, N. A. Index Fossils, 1, 1907, 

 p. 261, fig. 311f-h. 



Dalmanella perveta Hall and Clarke, ibid., 1892, p. 224, pi. 5C, figs. 13, 14. 



Orthis (Dalmanella) subaequata Winchell and Schuchert, Geol. Minnesota, 3, 

 1893, p. 446, pi. 33, figs. 30-36. 



Black River: Mineral Point, Wisconsin; Minneapolis, St. Paul, Cannon Falls, 

 Fountain, etc., Minnesota; Decorah and McGregor, Iowa; Auburn, Lincoln 

 County, Missouri; Montreal, Canada; New Jersey; Kentucky; etc. 



Stones River (Pierce Lebanon): Central Tennessee. 



Pianodema subsequata circularis (N. H. Winchell). 



Orthis circularis N. H. Winchell, 8th Ann. Rep. Geol. Nat. Hist. Surv. Minnesota, 



1880, p. 66. 

 Orthis (Dalmanella) subaequata var. circularis Winchell and Schuchert, Geol. 



Minnesota, 3, 1893, p. 452, pi. 33, figs. 46, 47. 

 Black River: Minneapolis, Cannon Falls, etc., Minnesota (Decorah)*; High Bridge, 



Kentucky (Lowville). 



Pianodema subaequata conradi N. H. Winchell. 



Orthis conradi N. H. Winchell, 8th Ann. Rep. Geol. Nat. Hist. Surv. Minnesota, 



1880, p. 68. 

 Orthis (Dalmanella) subaequata var. conradi Winchell and Schuchert, Minnesota 



Geol. Surv., 3, 1893, p. 449, pi. 33, figs. 37-39. 



Black River: Minneapolis, Minnesota; Decorah, Iowa; Janesville and Beloit, 

 x Wisconsin (Platteville); Montreal, Canada. 



Pianodema subaequata gibbosa (Billings). 



Orthis gibbosa Billings, Geol. Surv. Canada; Rep. Progr. for 1856, 1857, p. 296. 



(Not Billings, 1859=Hebertella vulgaris Raymond.) 



Dalmanella gibbosa Hall and Clarke, Pal. New York, 8, pt. 1, 1892, p. 224. 

 Orthis (Dalmanella) subaequata var. gibbosa Winchell and Schuchert, Geol. 



Minnesota, 3, 1893, p. 451, pi. 33, figs. 43-45. 

 Black River: Near Ottawa and Bellville, Canada; Minneapolis, Cannon Falls, 



etc., Minnesota; Decorah, Iowa; Mineral Point, Wisconsin; Island of Montreal; 



and Pallideau Islands, Lake Huron. 



Pianodema subaequata perveta (Conrad). 



Orthis perveta Conrad, Proc. Acad. Nat. Sci. Philadelphia, 1, 1843, p. 333. Hall, 

 Pal. New York, 1, 1847, p. 120, pi. 32, fig. 5. Emmons, Amer. Geology, 1, 

 pt. 2, 1855, p. 194, pi. 9, fig. 5. Hall, Geol. Wisconsin, 1, 1862, p. 42, fig. 7. 

 Billings, Geol. Canada, 1863, p. 130, fig. 57. Hall, 36th Rep. New York State 

 Mus. Nat. Hist., 1884, p. 75, pi. 3, fig. 6. Lesley, Geol. Surv. Pennsylvania, 

 Rep. P 4, 1889, p. 529, 6 figs. 



