PLATE VIII. 
Fig. 1. ORBICULOIDEA MISSOURIENSIS (Shumard)? p. 142 
1, An incomplete brachial valve, x2. Brentwood limestone, Station 
210 . 
Figs. 2, 2a. ORBICULOIDEA MINUTA n. sp p. 141 
2, 2a. Lateral and brachial views of the holotype, a brachial valve, 
x2. Brentwood limestone, Station 134. 
Figs. 3, 3a. RHIPIDOMELLA PECOSI (Marcou) p. 144 
3, 3a. Lateral and pedicle views of a small individual, x2. Brent- 
wood limestone. Station 210. 
Fig. 4. CHONETES ARKANSANUS n. sp p. 149 
4, Pedicle view of one of the cotypes, a pedicle valve, x2. Brentwood 
limestone. Station 210. 
Figs. 5-5c. RHIPIDOMELLA ALTIROSTRIS n. sp p. 143 
5, 5a, 5b, 5c. Pedicle, lateral, cardinal, and anterior views of the 
holotype, a pedicle valve. Hale formation. Station 139. 
Figs. 6-8. SCHIZOPHORIA RESUPINOIDES Cox p. 145 
6. The interior of a brachial valve of the usual size. Brentwood 
limestone. Station 134. 
7. 7a, 7b. Pedicle, lateral, and anterior views of a typical pedicle 
valve. Brentwood limestone, Station 135. 
8. Exterior of a brachial valve above the average size. Morrow for- 
mation, Station 304. 
Figs. 9-lOa. CHONETES CHOTEAUENSIS n. sp p. 150 
9. One of the cotypes, a pedicle valve. 10, 10a. Pedicle and anterior 
views of another of the cotypes, also a pedicle valve. Morrow 
formation. Station 295. 
Fig. 11. PUSTULA PUNCTATA (Martin) p. 172 
11, A typical pedicle valve. Hale formation. Station 137. 
Figs. 12-12b. PRODUCTUS NANUS Meek & Worthen p. 156 
12, 12a, 12b. Cardinal, lateral, and anterior views of a typical pedicle 
valve. Morrow formation. Station 304. 
Figs. 13, 14. CHONETES LAEVIS Keyes p. 151 
13, 14, Two typical pedicle valves. Morrow formation. Station 301. 
Figs. 15-15b. PUSTULA BULLATA n. sp p. 174 
15, 15a, 15b. Pedicle, lateral, and cardinal views of the holotype, a 
pedicle valve. Brentwood limestone. Station 145. 
Figs. 16-16b. PRODUCTUS sp p. 165 
16, 16a, 16b. Lateral, anterior, and cardinal views of the pedicle 
valve. Kessler limestone. Station 209. 
266 
