PLATE XII. 
Figs. 1-6. SPIRIFER ROCKYMONTANUS Marcou p. 181 
1, la, lb, Ic, 2, 2a, 2b, 2c, 3, 3a, 3b, 3c, 4, 4a, 4b, 4c. Pedicle, brach- 
ial, anterior, and lateral views of four specimens illustrating 
the stages in development. 5. A mature pedicle valve. 6, A 
mature brachial valve. Brentwood limestone, Stations 134 and 
135. 
Figs. 7-7c. SPIRIFER OPIMUS Hall p. 185 
7, 7a, 7b, 7c. Pedicle, brachial, anterior, and lateral views of a typ- 
ical individual. Brentwood limestone, Station 152. 
Figs. 8-9a. SQUAMULARIA TRANSVERSA n. sp p. 191 
8, 8a. Brachial and lateral views of one of the cotypes, a brachial 
valve. 9, 9a. Pedicle and lateral views of another of the co- 
types, a pedicle valve. Hale formation. Station 149. 
Figs. 10-lla. SPIRIFER GOREII n. sp p. 186 
10, 10a. Brachial and cardinal views of the allotype, a brachial valve. 
11, 11a. Cardinal and pedicle views of the holotype, a pedicle 
valve. Morrow formation. Station 304. 
Figs. 12-12C. PUGNOIDES TRIANGULARIS n. sp p. 175 
12, 12a, 12b, 12c. Pedicle, brachial, anterior, and lateral views of 
one of the cotypes. Hale formation. Station 137. 
Figs. 13-13b. SQUAMULARIA PERPLEXA (McChesney) p. 188 
13, 13a, 13b. Pedicle, brachial, and lateral views of a typical speci- 
men. Brentwood limestone. Station 135. 
Figs. 14-14b. EUMETRIA VERA (Hall) p. 197 
14, 14a, 14b. Pedicle, brachial, and lateral views of an average indi- 
vidual. Brentwood limestone. Station 152. 
274 
