608 



GEOLOGY 



Fig. 429. Kinderhook Fossils: a, Leplopora placenta (White), a compound 

 coral. 6, Actinocrinus senectus M. and G., a distinctively Mississippian erin- 

 oid; c, Dichocrinus inornatus W. and Sp., one of the earliest crinoids with 

 only two basal plates, d-h, brachiopods: d, Spirifer biplicatus Hall, a 

 species retaining an elongate hinge line characteristic of the Devonian: 

 e, Spirifer marionensis Shum.; /, Productella pyxidala Hall, of a genus 

 which had its greatest development in the late Devonian; g, Parn- 

 phorynchus striatocostatus (M. and W.), characteristic of Lower Kinder- 

 nook horizons of Iowa, Missouri, and Illinois; h, Prod 'net //.s- <ircuntiis 

 Hall, a genus developed from Productella, and characteristic of the 

 Mississippian and later Paleozoic periods; i, Grammysia hannibalensit 

 (Shum.), a pelecypod; /, Pernopecten cooperensis (Shim.), a pelecypod 

 characteristic of certain of the higher Kinderhook horizons; A-, rintiio- 

 stoma broadheadi S. A. M., a capulid gastropod; I, Macrocheilut blniri 

 (M. and G.); m, Prodromites gorbyi (S. A. M.), a widely distributed 

 cephalopod and the earliest form snowing secondary lobing of the su- 

 tures; n, Muensteroceras oweni (Hall), abundant in trie famous Kinder- 

 hook goniatite bed at Rockford, Ind.; o, Prdetus ellipticus M. and \\". 

 Trilobites were few in the Kinderhook, and this one illustrates their 

 characteristic lack of ornamentation; p, tooth of Clatlodm* .s'/>/-/m/" "' 

 St. J and W., a shark; q, a spine of Acondylacanthus gracilis St. J. and \V. 



