depressa, 830, 834. 
estella, 834, 836. 
instabilis, 836. 
var. incurva, 835, 834. 
patelliformis, 831, 826, 828, 830-833. 
perovalis, $30, 829, 831. 
pileolum, 836, 834. 
powersi, 829, 820*, 821, 828-831. 
richmondensis, $34, 835. 
rotunda, 835. 
rugatina, $35. 
semicarinata, 833. 
simplex, 834, 836, 
simulatrix, $33, 830. 
subrotunda, $34. 
valida, 832, 833. 
Arges, 744, 746, 750, 753, 754. 
armatus, 746. 
consanguineus, 746*, 753. 
contusus, 746, 753. 
eriopis, 753. 
hispidus, 753. 
phlyctenoides, 746, 753. 
wesenbergeusis, 746. 
var. paulianus, 744, 745*, 746, 753. 
Argilloecia, 632, 631. 
Aristerella, 524, 483, 485, 501. 
nitidula, 524, 509. 
Arthropoda, 699. 
Articulating groove, 697. 
Asaphids, 700. 
Asaphus, 700, 710, 711. 
canadensis, 705. 
canalis, TOT*. 
expansus, 701*, 700, 711. 
extans, 722. 
huttoni, 710. 
megistos, 7O1. 
platycephalus, 701, 706. 
romingeri, 705. 
suse, 708. 
vigilans, 712. 
Ascoceras, 764. 
manubrium, 764*. 
Asiphonida, 485. 
Astartella, 487. 
Astartide, 487. 
Atalanta, 844, 858. 
Atrypa reticularis, 724. 
Avicula aviformis, 532. 
trentonensis, 532. 
Aviculid, 532, 485, 489. 
Aviculopecten, 485. 
Aviculopinna, 485. 
Axinwa, 583, 584. 
sulplanata, 583. 
Axis of trilobites, 696. 
Bactrites, 764, 804. 
Bairdia, 632, 631, 690, 691, 693. 
anticostiensis, 691, 693. 
Bakeve.lia, 485. 
SCIENTIFIC INDEX. 
Barbatia, 533. 
Barychilina, 632, 631. 
Barychilinide, 632. 
Bathyurus, 722. 
extans, 722*, 723. 
longispinus, 722. 
schucherti, 724*. 
Spiniger, 723*. 
stonemani, 724, 
Baylea, 960. 
Beaks of Lamellibranchiata, 478. 
Beecherella, 632, 691. 
angularis, 692. 
carinata, 691, 692. 
cristata, 691. 
navicula, 692. 
ovata, 692. 
subtumida, 691, 692. 
Beecherellida, 691, 632, 692. 
Belemnites, 770, 773. 
Bellerophina, 857. 
CXXxiii 
Bellerophon, 914, 815, 844, $53, 854-858, 867, 868, 
875, 876, 881, 885, 896, 897, 898, 912, 915, 922, 923, 
926. 
acutus, 869*. 
affinis, 853, 
allegoricus, 853. 
antiquatus, 847. 
argo, 913. 
bicarenus, 853. 
bilineatus, 917, 853. 
bilokatus, 868, 872, 873. 
blandfordianus, 853. 
canaliferus, 853. 
cancellatus, 872, 848. 
capax, 921, 853. 
carbonarius, 855. 
charon, 853. 
clausus, 916, 853, 917, 920. 
combsi, 853. 
contortus, 850, 915. 
costatus, 853. 
crassus, 853. 
exigua, 896. 
explanatus, 854. 
fasciatus, 853. 
ferrussaci, 853. 
fiscello-striata, 896. 
gibsoni, 853. 
giganteus, 853. 
globulus, 853. 
hiulcus, 853. 
impressus, 853. 
jonesianus, 853. 
lindsleyi, 889. 
lineatus, 853. 
macer, 913. 
macromphalus, 850, 
macrostoma, S854. 
martini, 853. 
micromphalus, 856. 
miser, 853. 
mohri, 920, 853. 
montfortanus, 854, 
