TRENTON LIMESTONE. 



299 



a half mile northwest of this point, at Smith's quarry, the junction of the Upper Blue 

 beds and the Galena limestone with a few feet above and below is shown, completing 

 the series. This junction may also be seen between TurtlevUle and Shopiere. 



The quarries at Rockton, Illinois, present a magnificent section of the Upper Buii' beds 

 from layer B. IV upwards to the lower portion of the Upper Blue beds . 



These statements are given thus specifically that there may be the fullest opportimity 

 for verifying and utilizing the statements of this report, and that there may hereby be 

 furnished a basis for the more accurate study of the vertical, and, to some extent, hori- 

 zontal range of the exceedingly interesting fossils of these beds, which it is hoped will 

 be prosecuted by the geologists of tlie region. A series of collections carried on for years 

 under the favorable opportunities afforded by continuous quarrying, in which the exact 

 locality and horizon should be carefully noted, could not fail to show valuable results. 



Over one hundred species of fossils are known to occur in these beds, among which the 

 following identifications have been made : 



Buthotrephis succulens. 

 Steptelasma comiculum. 

 Chsetetes lycoperdon. 

 Cheetetes discoideus. 

 Stictopora elegantula. 

 Stictopora, n. sp. 

 Schizociinus nodosus. 

 PtUodictya recta. 

 Lingula, sp. und. 

 Orthis perveta. 

 Orthis phcatella. 

 Orthis testudinaria. 

 Orthis peetineUa. 

 Orthis tricenaria. 

 Orthis beUarugosa. 

 Strophomena camerata. 

 Strophomena altemata. 

 Strophodonta, sp. und. 

 Sfcreptorhynchus defiectum. 

 Sti-eptorhynchus subtentum. 

 Leptsena sericea. 

 RhynchoneUa, sp. und. 

 Ambonychia attenuata. 

 Ambonychia, n. sp. 

 Ambonychia lameUosa. 

 Cypricardites Niota. 

 Cyprioardites rotundatus. 

 Cypricardites ventricosus. 

 Cypricardites, n. sp. 

 Tellinomya nasuta. 

 TeUinomya alta. 

 TeUinomya Iphigenia. 

 TeUinomya levata. 

 Tellinomya ventricosa. 

 Modiolopsis superba. 

 Modiolopsis plana. 

 Raphistoma lenticularis. 



Raphistoma Nasoni. 

 Troohonema ambiguum. 

 Troohonema umbiHoatum. 

 Trochonema Beloitense, n. sp. 

 Plurotomaria subconica. 

 Murchisonia bicincta. 

 Murchisonia gracilis. 

 Murchisonia hehcteres. 

 Murchisonia pagoda. 

 Murchisonia trioarinata. 

 Cyclonema percarinatum. 

 Subuhtes elongatus. 

 Chsospira occidentalis, n. sp. 

 HeHcotoma planulata. 

 Maclurea Bigsbyi. 

 Metoptoma perdvalis, n. sp. 

 Bellerophon bUobatus. 

 Bellerophon Wisconsinensis, n. sp. 

 Bucania Buelli, n. sp. 

 Bucania punctifrons. 

 Bucania bidorsata. 

 Pterotheca attenuata. 

 HyoUthes Baconi, n. sp. 

 Gyroceras, sp. und. 

 Cyrtoceras annulatum. 

 Cyrtoceras comiculum. , 

 Cyrtoceras eugium. 

 Cyrtoceras Neleus. 

 Oncoceras abruptum. 

 Oncoceras Alceus. 

 Oncoceras Lycus. 

 Oncoceras Pandion. 

 Oncoceras plebeium. 

 Oncoceras, sp. undescribed. 

 Oncoceras, sp. undescribed. 

 Orthoceras anellum. 

 Orthoceras multicameratum. 



