EXPLANATION OF PLATES 
PLATE I 
INGE TIGHTS HRS BOO OCOta SITS Gar OO a oc ate dia cinn Omico no 0G oF arreciva bode 
(1, 2) Respectively & 1 and X 2 views of a pedicle valve showing an 
impression of the interior with its long, low, median ridge, figured 
specimen, U.S.N.M., 125311. Locality U.O. 2204-3. 
(3) Plasticine impression showing a replica of the exterior of a crushed 
brachial valve, < 1, figured specimen, U.S.N.M. 125531. Locality S50. 
MV OR DIUTE SPs DSi oka nim) a oiatesei ete suave, 8 ewe wr ghadtaeva\ gaya arena: ceaiey cau aka tay eteeneioteltalelabaial 
(4, 5, 7) Respectively posterior, side, and ventral views of a pedicle 
valve showing interarea, <1, figured specimen, U.S.N.M. 125315. 
Locality Stor. 
(6) Exterior of a poorly preserved brachial valve, 1, figured speci- 
men, U.S.N.M. 125312. Locality U.O. 2204-3. 
C. Paeckelmanma aff. Chonetes alatus Stuckenberg.................-.-+--- 
(8) Exterior of an imperfect pedicle valve with outline restored, X 3, 
figured specimen, U.S.N.M. 125316. Locality S41. 
DD NPVIGER CULE IST) WE) aicyctapevescisySveleeie cle exsis. siaveiercte cieke om tate Ciera soles oleialei schol cuekerhetetatete 
(9) Side view of a specimen broken through the middle, X 1, figured 
specimen, U.S.N.M. 125313. Locality 637. 
POU ECTUMC ILE SPs. Tis) sicie. aie.a:& aeaun senate ack shes os tals tenia ai olen hata ea ein ca ere 
(10, 11) Exterior of an imperfect pedicle valve showing deep sulcus, 
<1 (with outline restored) and X 2, figured specimen, U.S.N.M. 
125468. Locality S103. 
Eis MHL RAO MICTIC “SEY, (Lx as nich save gsieish 6.4s.a)s8 5 Se die, taleta tars aielshsrs sminw arameaee 
(12) Exterior of a small pedicle valve, < 2, figured specimen, U.S.N.M. 
125314. Locality Stor. 
MO PUTE UTES SD. Te occ ss tec taba nae wsla tien co Re geese te ae emit ne ae eeieters 
(13) Dorsal view of a complete specimen with broken margin, X 1, 
figured specimen, U.S.N.M. 125463; (14-18) respectively posterior, 
ventral, anterior, dorsal (with margin restored), and side views of the 
same specimen, X 2. Locality S46. 
H. Chonetes pygmoideus Cooper, new SpecieS.....0.....cccccecencccccces 
(19-23) Respecively anterior, posterior, ventral, side, and dorsal views 
of the holotype, U.S.N.M. 125469; (24-26) respectively side, dorsal, 
and ventral views of the holotype, & 2. Locality S3o. 
De LGHENCTES “Spy UG. 2 ceieihc fe o ore d Low aly arse ol at eae ee he cette ehh oe eras 
(27-31) Respectively dorsal, ventral, anterior, posterior, and side views 
of a complete but somewhat exfoliated specimen, X 1, figured speci- 
men, U.S.N.M. 125470a; (32) same specimen as preceding, X 2, 
showing pits left by pseudopunctae when shell was exfoliated; (33) 
rubber replica of the exterior of a brachial valve showing the 
costellae, < 2, figured specimen, U.S.N.M. 125470b. Locality S68. 
(34) Impression of the interior of a pedicle valve showing median 
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25 
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55 
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