REPORT OF THE STATE PALEONTOLOGIST 1901 555 



the latter, which are highly lustrous and clearly had not been 

 •exposed to any maceration before becoming embedded. This 

 bed must be regarded as a veritable treasure chamber, as it 

 -contains numerous perfect colonies which are neatly spread out 

 on the surfaces of the slabs and retain all parts, the central 

 disk, sicula and virgula; and some species occur in all their 

 growth stages. In one layer, a great number of the specimens 

 are pyritized, specially so the numerous hydrosomas of 

 Phyllograptus ilicifolius and of the dichograptids. 

 This material will allow an investigation into the structure of 

 these forms. 



The writer abstains in this publication from describing the 

 numerous forms which are not identifiable with species hitherto 

 known on this continent, partly because time has not yet 

 allowed a satisfactory illustration nor a thorough comparison 

 with related species known from foreign graptolite shales; and 

 partly because a monograph of the graptolites of New York 

 is thought to furnish a more appropriate receptacle for such, 

 descriptions. 



The following is a list of the species found in graptolite 



toed 2: 1 



1 Dendrograptus sp. nov. Hall r 



2 D. cf. gracilis Hall r 



3 Dictyonema sp. nov. r 



4 Callograptus salteri Hall r 



lr Phe peculiarity of most graptolite beds, that the separate layers of 

 the same bed differ in the relative prevalence of certain species and hence 

 in the general aspect of the assemblages, is strongly marked in this; cer- 

 tain layers are nearly covered with specimens of a new Bryograptus, 

 others with those of the various tetragraptids and again others with the 

 branches of dichograptids. Fossil lists of the faunules of these thin 

 layers fail, however, to bring out a difference in their composition, or in 

 the number of species. It appears, therefore, that all these different 

 assemblages lying so close together in the rock, were derived from con- 

 temporaneous denizens of the sea. These graptolites either lived together 

 in shoals, or more probably, while slowly settling, became separated 

 according to their size and weight. 



If, therefore, a form asBryograptus sp. nov. is listed as extremely 

 common (ccc) this statement does not refer to all layers of the bed, but 

 only to one or to a few. 



