CONTENTS 



PAGE 



Introduction 489 



History of the Hudson river beds 490 



Result of former investigations 512 



Discovery of outcrops (stations) with fossils. 513 



Description of stations. ., 513 



A Lorraine beds 513 



B Utica beds 519 



G Middle Trenton beds 533 



D Normans kill beds (lower Dicellograptus zone) 538 



Conglomerate bed of lower Trenton aspect in shale i. . . . . 644 



Conglomerate bed on Rysedorph hill 546 



Extension of zone of Normans kill beds. (Lower Dicellograptus beds) 550 



Taxonomic position of the Normans kill graptolite beds 550 



Explanation of the overturn of the strata ,. 552 



Clastic development of Trenton in Hudson river valley ,. . . . 558 



Discontinuity of faiinistic succession in Trenton and Utica beds 661 



Discussion of the validity of the term, " Hudson river group " 564 



Summary ,. . . . 567 



Descriptions of new fossils found in the described shales 569 



Description of map 581 



References 581 



Explanation of plates 586 



Index 589 



