PREFACE 



The first instalment of the graptolites of New York was published as 

 Memoir 7, New York State Museum. It comprises a resume of the present 

 status of our knowledge of graptolites and descriptions of the graptolites 

 of the Upper Cambric and Lower Champlainic (Lower Ordovicic). The 

 present volume contains the remainder of the graptolites, i. e. those of the 

 Middle and Upper Champlainic, the Siluric and Devonic. 



The correlation of the New York graptolite beds with those of other 

 parts of America made it necessary to institute comparisons with graptolites 

 from other states and the occasion has been used to describe and figure the 

 relatively small number of forms from other parts of the country as far as 

 these have been made accessible to us through the kindness of colleagues. 

 The rich faunas of Canada have been excluded since we are informed that 

 Professor Lapworth, the leader among modern investigators in this field, 

 has been studying them for more than a decade. 



During the prosecution of this investigation, the desirability of some 

 introductory chapters to the second part of the treatise has urged itself 

 upon the writer. These are wholly supplementary to those of the first part 

 and contain bibliographic references, and morphologic and phylogenetic 

 observations regarding the later graptolites here described. Some obser- 

 vations have been incorporated in the introduction because they could be 

 dealt with more advantageously here than when scattered through generic 

 and specific descriptions. The discussion of the range of the forms and the 

 geographic distribution of the zones of the higher graptolite beds had for 

 obvious reasons also to be reserved for this volume. A more complete cor- 

 relation table of the zones incorporating those of the first volume is added ; 

 and also a synoptic table of the range of the genera of the higher beds. 

 Finally, we have in completion of our work inserted a synoptic and syn- 

 onymic list of the graptolites known from North America. A few notes 

 on forms which at times have been considered as graptolites have been 

 added in an appendix. 



