'_'7() CAKHONIKI'IUOUS FORMATIONS AND KAUNAS OF COLOKADO. 



BRAOIIIOPODA. 



RHIPIDOMELLA Ochleil, ls!»l. 

 Uiiii'ii)():\iKi,i.A i'uia'HkTjLa llcrrick. 



l.SiSS. (Mlih vanuxcmi var. palcliellnx. 1 Icrrick, Sci. J^ab. Dcninon Univ., Bull., Vdl. li, ii. lis, jil. 5, li};. i). 



Waverly grouiK Licking County, Ohio. 

 l,Siir>. Orlliis vanuxcmi \i\T. gracilis. Herriok, Geol. Snrv. Ohio, Rept., vol. 7, pi. 21, lij:. II. 



Kimlerhook: Granville, Ohio. 

 1899. RhipidomellamicheUni. Girty, U. S. Geol. Surv., Mon., vol. 32, pt. 2, ji. o21. 



Madison limestone: Yellowstone National Park. 



Thi.s i.s a tfinall, poorly characterized form, not materially different from .several 

 other representatives of the genus, and it may perhaps include what are only small 

 or immature examples of some of the larger species such as Rh. oweni. All of 

 my specimens, however, are small, rai-ely exceeding 15 mm. in greatest diameter. 

 They are often somewhat transverse. The striation is ver}^ fine (about 20 striaj in 

 the space of 5 mm.) and appears to be tubulose and spinose. A form which is 

 believed to be the same occurs in the Madison limestone of Yellowstone National 

 Park, and I at one time identified it as JRh. ndchelini. A similar and probably 

 identical species is found in the Cuj^ahoga shale of northern Ohio, and to a closely 

 related, if not identical form, occurring at a somewhat higher horizon in central Ohio, 

 Herrick has given the name Orthis vanuxemi var. pulchella^ which I have adopted 

 for the Colorado form under discussion. 



Locality and horizon.— '^•nn Juan region (stations 2379, 2382, 238i, 2385); Ouray 

 limestone. Crested Butte district (station 2358); Leadville limestone. 



OETHOTHETES Fischer de Waldheim, 1829. 

 Oethothetes in^qtjalis Hall. 



18.58. Ortlm ineqvulis. Hall, Geol. Surv. Iowa, vol. 1, pt. 2, p. 490, pi. 2, figs. 6f(-c. 



Chemung group : Burlington, Iowa. 

 1865. Slreptorhynchus mequalis. AVinchell, Acad. Nat. Sci. Philadelphia, Proc, p. 117. 



Marshall group: Weymouth, Medina County, Ohio, 80 feet below conglomerate. 

 1870. liemiproniles iiiequalis. Winchell, Am. Phil. Soc, Proc, vol. 11, p. 251. 



AVaverly group: Newark and Granville, Ohio; near Shafers, Pa. 

 1877. Streptoniynchus equivalvis. Hall and Whitfield, TJ. S. Geol. Expl. 40th Par., Rept., vol. 4, p. 252, 

 pi. 4, figs. 1, 2. 



Waverly group: Ogden and Logan canyons, LTtah. 

 1883. Sirepiorlnjncluis a-quivalvis. Hall, Bept. New York State Geol. for 1882, pi. (IIA) 42, figs. 20-23. 



AVaverly group: Burlington, Iowa. 

 1892. OrthotJietes mequalis. Hall and Clarke, Pal. New York, vol. 8, pt. 1, ])1. 9A, figs. 20-23. 



Kinderhook group: Burlington, Iowa. 



