INDEX. 



]'Bla<-k-faoe figures indicate pag^s on '^•hich detailed descriptions occur; 



italic are synonyms.] 



J^. Page. ; 



Acantliopecten - 41 7-418 



carboniferus 242, 247, 248, 260, 251, 253, 260, 418 



Acervularia 34 



34 



italic figures indicate illustrations; names : 



sp 



Aclisina stevensiana 2:^3, 459-460 



Allerisma capax 38, 438 



elongatum 438 



terminale 247,251,253,261.437-4;{8,5i/* 



AUorisma cnsiformis 437, 438 



learenwortltensia 436 



regulai is -137 



subcuncata 437 



subcuTieatum 35, 437, 438 



terviinaUs 437 



topck(iensis 439 



Amplexu.s 31 



westi 322 



zaphrentiformis 34, 322 



sp 237,248,249,250,259,322 



Ambocelia gcmmula 394 



Amboccelia planicon vexa 248, 249, 251, 260, 393, 394-395 



plannconvcJia 395 



Animas River, fossils from near 337 



rocks exposed on 131 



Anomi tes lineatus 388 



intnctatus 368 



ATithracujAera polita 430 



Area striata 443 



Arehaeoeidaris cratis 35, 237, 242, 257, 259, 331 



edgarensis 331 



gracilis 38 



Jiallianus 332 



longispinus 38 



megastylus 330, 331 



ornata 242, 243, 249, 250, 259, 331 



ornatus 38, 331 



ourayensis 257, 329, ^e 



triplex? 247, 250, 259,330 



trudifei^ 35,242,259,330-331 



Arehean unsubmerged mountain masses, in Rocky 



Mountains, discussion of 210-211 



Arohimedes 31,34 



sp. 



34 



Areas, classification of 27-138 



Arkansas River, rocks exposed on 92 



Sa watch quartzite near 142 



section in canyon of 92-93 



Arkansas sandstone, age and equivalents of 190, 191, 210 



occurrence and character of 88, 165, 178, 179, 180-181 



Page. 



Asaphus (Megalaspis) 152 



Aspen, fossils from 269 



Slaroon conglomerate at 175 



Parting quartzite at 157, 158 



Red Beds at, thickness of 200 



Sawatch quartzite at 140 



section at 53 



Yule limestone at, thickness of 200 



Aspen district, fossils from, description ot 220, 



269, 270, 273, 283-284, 313, 314 



Leadville limestone in 163 



Maroon conglomerate in 173 



Ordovician rocks in 148 



Weber formation in 172-173 



Astarte f/ibhosa , 447 



mortmiensis _448 



Astartella? gurleyi 253, 460 



Athi/ris argentea 405 



clay toni 296 



orbicularis 407, 408 



plmiosulcaia 407, 408 



mhlavicllosa '. 407, 408, 409 



siibqiiadraia 296,297 



subfilita 77, 103, 131, 224, 403, 404. 405 



Athyrus orbicularis 407,409 



Atrina 434 



Aubrey group, age and stratigraphic place of 197, 210 



composition and thickness ot 30,204 



interruption in sedimentation at top of 31 



Aubrey group, lower, character and thickness of 197 



fossils from 34,35 



Aubrey group, upper, character, thickness and strati- 

 graphic place of 32, 197 



fossils from 35 



Aubrey limestone, stratigraphic place and equiva- 

 lents of 178, 208 



Aubrey sandstone, equivalents of 207 



Aulopora prosseri 324, 325 



Avicula ■ 60, 62, 174 



pinnEcfocmis 432, 433 



recta-laterarea 415 



speluncaria 428, 429 



Aviculopecten fiO. 62, 174 



carboniferus 417, 418 



coloradoensis 38 



interlineatus 236, 237, 260, 410, 510 



occidentalis 38, 



237, 248, 250, 251, 253, 260, 414-415, 416, 510 



pellucidus 248,251,260,415 



533 



