BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 28, pp. 959-964 DECEMBER 19, 1917 



PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



WERE THE GRAPTOLITE SHALES, AS A RULE, DEEP OR 

 SHALLOW WATER DEPOSITS?^ 



BY AMADEUS W. GRABAU AND MARJORIE o'CONNELL 



{Presented before the Paleontological Society December 28, 1916) 



CONTENTS 



Page 



rntroduction 959 



The problem stated 960 



Typical graptolite shales 960 



The Swedish region 961 



The Moffatdale region. . . , 961 



Conclusions 964 



Introduction 



During the last four or five decades the two chief objects in the study 

 of the graptolites have been, first, the refinement in classification, together 

 with the careful description of new species and the determination of onto- 

 genetic and phylogenetic relations; and, secondly, the determination of 

 the exact stratigraphic or zonal distribution of the graptolites and the 

 correlation of these zones over wide geographic areas. Questions of hab- 

 itat and mode of distribution were considered only incidentally, though 

 such keen students as Lapworth, Wiman, Ruedemann, and Hahn have 

 dealt with these problems separately. The conclusions reached by Lap- 

 worth^ and published in Walther's 'Veber die Lebensweise fossiler Meer- 

 esthiere" have been quite generally accepted. His belief is that the grap- 

 tolites, w^hich lead a floating existence either as holoplankton or epiplank- 

 ton (attached to sea-weeds), sank to the bottom of the deeper littoral, 

 where no other organisms lived and where they were buried in the fine 

 mud which was rendered carbonaceous by the decaying sea-weeds. The 



1 Manuscript received by the Secretary of the Geological Society April 30, 1917. 



2 Zeit. d. deutsch. geolog. Gesell., Bd. xlix, Heft ii, pp. 209-273 ; Lapworth's letter, pp. 

 241-258. 



(959) 



