INDEX. 



815 



Acrotreta claytoni, described 680 



general geographic and stratigraphic distribution tab- 

 ulated 105 



surface features mentioned ■. - 672 



t>'pe specimen figured PI. LXXIV, fig. 3 



concentrica, described 681 



general geographic and stratigraphic distribution tab- 

 ulated 105 



type specimen figured PI. LXXVII, fig. 1 



conula, described 681 



general geographic and stratigraphic distribution tab- 

 ulated lOG 



type specimen figured PI. LXXV, fig. 2b 



convexa, described 682 



compared with Acrotreta gemmula 686 



general geographic and stratigraphic distribution 



tabulated 106 



type specimen figured PI. LXVI, fig. 6 



" ? costata,^' discussed 674 



cuTvata, described 682 



cardinal area discussed 305 



compared with A crotreta idakoensis 6SS 



A cTotreta microscopica 693 



Acrotreta ophirensis 697 



A crotreta sagittalis transversa 673 



A crotreta ulricki 714 



general geographic and stratigraphic distribution 



tabulated 106 



type specimen figured PI. LXVIII, fig. la 



definita, described 683 



cardinal area discussed 305 



compared with A crotreta bellatula 678 



Acrothele bellula 631, 637 



A crotreta rudis 702 



general geographic and stratigraphic distribution 



tabulated ., 106 



type specimen figured PI. LXrV,fig. 2c 



depressa, described 683 



compared -with Acrotreta definita 683 



A crotreta rudis 702 



general geographic and stratigraphic distribution 



tabulated 106 



type specimen figured PI. LXVI, fig. 8 



eggegrundensis, described 684 



general geographic and stratigraphic distribution 



tabulated 106 



stratigrapliic position of bowlder containing 454, 864 



type specimen figured PI. LXX, figs. 2a-c 



emmonsi, described 684 



general geographic and stratigraphic distribution 



tabulated 106 



stratigraphic position mentioned 318 



type specimen figured PI. LXV, fig. 6 



gemma, described 685 



compared with Acrotreta depressa 683,684 



A crotreta ovalis 699 



A crotreta schmalenseei 709 



discussed 673 



general geographic and stratigraphic distribution 



tabulated 106 



mentioned 675, 691 



species referred to mentioned 673, 689 



type specimen figiued PI. LXVI, fig. 1 



gemmula, described 686 



compared with A crothyra proavia 717 



Obolus C Westonia) ella 674 



general geographic and stratigraphic distribution 



tabulated 106 



type specimen figured PI. LXVI, fig. 3a 



gracia, described 687 



general geographic and stratigraphic distribution 



tabulated 106 



type specimen figured PI. LXVI, fig. 5a 



" tguliclmi," type oi Discinopsis 720 



zdahoensis, described 687 



compared -with. Acrothele suhsidua 633 



Acrotreta argenta 674 



Acrotreta curvata 682 



Acrotreta 



Acrotreta idahoensis—ContinuQd. 



compared with A crotreta eggegrundensis .,.., 6 



Acrotreta emmonsi. 6 



Acrotreta cf. idakoensis.. 6 



Acrotreta idakoensis alta C 



Acrotreta marjumensis f 



Acrotreta microscopica C 



A crotreta microscopica tetonensis f 



Acrotreta neboensis ., f 



A crotreta pyxidicula / 



A crotreta signalis 'i 



Acrotreta spinosa 't 



false area in, discussed ( 



general geographic and stratigraphic distribution tab- 

 ulated - 



position assumed by shells in settling to the bottom 



discussed ' 



stratigraphic distribution mentioned ( 



type specimen figured PI. LXV, fig. 



cf. idakoensis, described i 



general geographic and stratigraphic distribution 



tabulated ; 



idakoensis alta, described i 



compared with Acrotreta attenuata i 



Acrotreta depressa 683, i 



Acrotreta gemma < 



Acrotreta idakoensis sulcata i 



Acrotreta pacifica 



general geographic and stratigraphic distribution 



tabulated 



stratigraphic distribution mentioned 



type specimen figured PL LXV, fig. 



idakoensis sulcata , described 



compared with A crotreta lisani 



A crotreta uplandica 



general geographic and stratigraphic distribution 



tabulated 



type specimen figured PI. LXV, fij 



indkoans, described 



general geogi-aphic and stratigraphic distribution 



tabulated 



type specimen figured PI. XV, fi 



inflata, described 



compared with A crotkyra minor . . , , 



Obolus ( Westonia) ella 



general geographic and stratigraphic distribution 



tabulated ., 



type specimen figured PI. LXXVI, fi 



"inflata ovalis," discussed 



liutorgai, described 



cardinal area discussed 



compared with Acrotkele bellula 



Acrotreta attenuata 



Acrotreta concentrica 



Acrotreta eggegrundensis 



Acrotreta sagittalis transversa 



deltidium discussed 



general geographic and stratigraphic distribution tab- 

 ulated 



type specimen figured PI. IvXV, fig 



lisani, described 



general geographic and stratigraphic distribution tab- 

 ulated 



type specimen figured PI. LXVIII, figs. 3, 2 



marjumensis, described 



cardinal area discussed 



general geographic and stratigraphic distribution tab- 

 ulated 



type specimen figured PI. LXXVIII, fi 



microscopica, described 



compared with Acrotreta microscopica missouriensis . , . 



A crotreta microscopica tetonensis 



Acrotreta ovalis 



Acrotreta schmalenseei 



Acrotreta sJiantungensis 



Acrotreta signalis 



false area in, discussed 



general geographic and stratigraphic distribution tab- 

 ulated 



type specimen not figured. 



