INDEX. 



IV 



Xucula Bey rich! 589 



Nucula pan- a 589 



Ogle county, gt ology of 104 



Oi;le county, foi-iuutions of 107 



( t^lr county, surface deposits of 107 



O::le i oini ty, ecouom. geology of 119 



Onyt.-lia.stfr 474 



( )nychaster Barrisi 47(3 



Onyclmstcr tiexilis 510 



Onvchocrimis exculptus 498 



( hiychociimis Whittieldi 552 



( (hgoporus nobilis 476 



Orthis carbonaria 571 



Orthocrrus Rushensis 612 



Ortboneina coniea 590 



Pala-chinus gracilis 473 



Peat 72 : 102. 120, 160 



Pentremites Burlingtoneusis 461 



Pentremites Wortheui 506 



Peutremitcs Woodmani 506 



Pforia county, geology of 235 



Peoria county, .section of stratified rocks 238 



Peoria county. Arnu-t &. Duke's mines 240 



Peoria county. Kingston mines 241 



Peona count \. Walter Treasure's mines 243 



Peoria county, Elmwood boring 244 



Peoria county, econom geology of 247 



Phillipsia. bufo 52& 



Phillipsia. Portlockii 525 



Phillipsia, Sangaiuonensis 615 



Phillipsia scitula 612 



Pholidocidaris 510 



Pholidotidaria irregularis 512 



Platy eeras equilatera 518 



I'latyceras fissurella 519 



Platyccras infundibulnni 517 



Platycerus spinigfrum 594 



Platyceras unciun 516 



Platyt-rinites a-qualis 456 



Platycrinites Burlingtonensis 452 



Platyerinites heniisphericus 334, 506 



Platycrinites Halli 454 



Platycrinites ineomptus 459 



Platycrinites parvulus 555 



Platycrinites planus 4.V2 



Platycrinitt's subs]iinosus 452 



Platycrinites temiibrachiatus 4.";0 



Placunopsis carbonaria 578 



Platt coal shaft 197 



Pleurotomaria conoides 603 



Pleurotoinaiia Coxana 600 



Pleurotomaria Gurleyi pi 30, fig. 6 



Pleurotomaria sjiironerna 601 



I'leurotoniaria valvatiformis 602 



Plenropliorus oblougus 589 



Polyjiliemopsis cbrysallis 596 



PoTeriocrinites ISisselli 546 



PoteriiH'rinites concinnus 4;0 



PoteriiM-rinites Hardinensis 533 



Poteriocrinites Macoupinensis 561 



PAGE. 



Poterioerinites peii>lexus 405 



Praii ies. origin of 10 



Productus Lasallensis 569 



Productus longispiuns 569 



Productus Xebraseensis 569 



Productus punctatus 569 



Protaster gregarius 509 



Pterotocrinus depressus 559 



Putnam county, geology of 21 1 



Putnam county, econom. geology of 216 



Kbynchonella Osagensis 571 



Rock Island county, geology of 217 



Rock Island county, surface deposits of 218 



Rock Island county, Coal Measures of 219, 228 



Kock Island county Carbon cliff section ,220 



Rock Island county Coal Valley section 229 



Rock Island county Coal creek section 230 



Rock Island county, econom. geology of. . .224, 233 



Saccocriuus 395 



Saugamon county, geology of 306 



Saiigamou county, superficial deposits of 307 



Sanganum county, stratified rocks of 309 



Sangamon county Howlett shaft section 313 



Sangamon county Pleasant Plains section 314 



Saiii:aiiion county Barclay shaft section 314' 



Sangamon county, econom. geology of 317 



Scaphiocrinus aequalis 494 



Scapbiocrinus Bayensis 550 



Seaphiocrinus carbonarius 562 



Scaphiocrinus Coreyi , 494 



Scapbiocrinus clio 408 



Scaphiocrinus delicatus , 407 



Scaphiocrinus depressus 492 



Scaphiocrinus fiscellus 4-34 



Seaphiocriuus heniisphericus , 561 



Scaphiocrinus Huntsvillae 534 



Scapbiocrinus juvenis 417 



Scaphiocrinus Me Adainsi 495 



Scaphiocrinus macrodactylus 415 



Scaphio rinus 1 1 am is 403 



Seaphiocriuus notabilis 410 



Scaphioi-rinus peuicillus 414 



Scapbiocrinus Randolphensis 551 



Scaphiocnmis rudis 413 



Scaphiocrinus scalaris 431 



Seaphiocriuus striatus 413 



Scaphiocrinus Tethya 419 



Scaphioeriuus nnicus 493 



ScbizodiiB ampius 579 



Schizodus curt us , 5^53 



Schizodus perelegans 581 



Scbix.odus Rossicus pi. 2fi, figs. 17, 18 



Serrell's coal, analysis of 197 



Sheffield coal, analysis of ng 



Soils 8, 121 



Spirifer Fultonensis 



Spirifer cameratus , 573 



St<-i)henson county, geology of 57 



Stephenson county, formations of 60 



Stepheuson county, econom. geology of 71 



