No. 186.] 45 



NOTES UPON THE GENUS GMPTOLITHUS ; 



;"W1TH KEMARKS UPON SOME OF THE SPECIES, THEIR MODE OF GROWTH, AND MANNER 



OF REPRODUCTION. 



[ Supplement to Volumes I & II of the Palaeontology of New- York.] 



The short time allowed, and the limited means at my disposal, for 

 the investigations and collections for the first volume of the Palaeon- 

 tology of New- York, prevented that careful and continued examina- 

 tion of many of the fossiliferous beds which becomes so desirable in 

 the present state of the science and the requirements of geology*. 

 Notwithstanding this, however, fifteen species of Graptolites were 

 determined, ten of which were at that time new; while of those 

 identified with European species, we may still raise the question as 

 to positive specific identity, and, with the addition of new material, 

 the subject at this time requires a thorough revision. At that time 

 the peculiar branching forms of the genus were first made known, 

 and, so far as I am aware, a greater variety of form and character 

 illustrated than had previously been observed. 



Two other species from the Clinton group were described in the 

 second volume of the Palaeontology of New-York, one of these being 

 referable to the Genus Gladiolites. In the same volume I described 

 the Genus Dictyonema, referring it to the Family Graptolitide^. 



In a short paper published in the Proceedings of the American 

 Association for the Advancement of Science for 1849, I stated that 

 the Graptolites were not represented in the higher Silurian, Devonian 

 or Carboniferous strata. Subsequently, in the same year, however, I 

 determined the Genus Dictyonema to belong to the Graptolitidese; 

 and this opinion was expressed in the second volume of the Palae- 

 ontology of New- York in 1850 (though the volume was not published 

 till 1852). The Dictyonema, on farther examination, has proved to 

 be an unequivocal graptolitic genus, consisting of radiating filaments 

 or branches which are connected together by transverse bars, and 

 form flabellate or funnelshaped fronds growing from a radix, and 



* The first volume of the Palaeontology of New-York was published in less than four years 

 from the time the-work was placed in my charge, and this without an assistant of any kind 

 furnished by the State ; and the entire collections, except a small number previously in the 

 State collection, were made at my private expense. This state of things, and the comparative- 

 ly imperfect knowledge of the rocks at that time possessed by every one, may offer some 

 excuse for many omissions and some imperfections. 



