STUDY OF THE GRAPTOLITES. 255 



not aware that graptolites have been found in any authentio- localities of 

 that formation, unless the Diplograptus secalinus of the Hoosic slates be 

 referred to that group.* With these exceptions, therefore, these fossils 

 of the group are known only in Canada and Newfoundland. 



The Trenton limestone, while furnishing two species of Graptolithus 

 in New York, gives at the west no specimens of the genus proper ; but 

 we have one Dicttonema, a Buthograptus, and an OldhamiaI in the same 

 formation in Wisconsin, though not elsewhere known to me at this time. 



The Utica slate at Utica abounds in the remains of graptolites, and these 

 fossils are of frequent occurrence at Oxtungo Creek, in the Valley of the 

 Mohawk. It is probable that some of the localities referred to the Hudson 

 river formation may be in the Utica slate , which, owing to the disturbed con- 

 dition of the strata, is not separable from the succeeding slates of the group. 



In the Hudson river formation the characteristic graptolites, of nume- 

 rous species, have been found, in greater numbers than elsewhere, at 

 Norman's Kill, near Albany ; but they occur at Stuyvesant's Landing, 

 and at the city of Hudson; while some species have been found near 

 Baker's Falls on the Hudson river, and at Ballston and Saratoga, New 

 York. Graptolites, of species identical with, and similar to those of the 

 Hudson river formation, have been found by Dr. Emmons in the shales of 

 Augusta county, Virginia, and also in Tennessee. 



The more characteristic species of the formation, G.pristis, G. bicornis, 

 G. ramosus, G. sextans, G. divaricatus, and G. gracilis, have been recognized 

 among the collections of the Canada Geological Survey, from the Hudson 

 river formation in the Valley of the St. Lawrence : and a species of 

 Diplograptus occurs in the Utica slate at Lake St. John. In the exten- 

 sion of this formation westward, a few species only have been found in 

 Central and Western New York; among these, G. pristis is the most 

 common, while G. Ucornis is more rarely seen. In Ohio, we have no 

 more than two species from rocks of this formation; while extensive 

 collections from the same formation in Wisconsin and Iowa have afforded 

 only three species (all unlike those from Cincinnati), and one of these 

 has been found in beds of the same age in Illinois. In the catalogue of 

 fossils appended to the Geological Report of Missouri, no mention is 

 made of the occurrence of Graptolitidae in any of the formations. 



The greatest accumulation of materials at the epoch of the Hudson 

 river formation has been in the direction from northeast to southwest ; 



* A single branching form, the G. milesi, has been published in the Geological Report of Ver- 

 mont. The specimen was found in a boulder of slate, but it is probably of the Quebec group. 



