160 PALEONTOLOGY OF NEW YORK. 



The Geographical distribution of the species of Tentaculites has received little 

 attention, and we are not prepared to give any complete information upon the 

 subject. In the State of New York no species have been described from strata 

 below the Clinton group. Of the two species of this formation, one is known 

 in the green shales of Rochester and central New York, and has not been 

 recognized beyond the limits of the State. The other species described from 

 the same horizon is known only in Canada West, near the head of Lake 

 Ontario. 



The Tentaculites Niagarensis occurs in the upper beds of the Clinton group, 

 and in calcareous bands in the shale of the lower part of the Niagara group, 

 but has not been traced beyond the limits of central and western New York. 

 Among all the Niagara fossils from Iowa and Wisconsin, I have not recognized 

 a single species of the genus ; and several thousands of all classes of fossils of 

 this age from Waldron, Ind., have passed under review without revealing a 

 single specimen of Tentaculites. In strata of the age of the Niagara group at 

 Cumberland, Md., and in the same layers, associated with well known Niagara 

 fossils, a species occurs very similar to, but more slender than T. gyracanthus, 

 but which is unknown to us beyond that immediate neighborhood. 



The T. gyracanthus is abundant in eastern New York at the base of the 

 Helderberg mountains and in Schoharie ; it is not known beyond a distance of 

 fifty or sixty miles westward, although having an extension to the southwest- 

 ward, along the trend of the formation, of more than three hundred miles. It 

 is of common occurrence, in the same beds, in the southern part of the State and 

 the adjacent portions of New Jersey ; and at Warrior's Ridge, in Huntington 

 county, Pa., it is as abundant as at the base of the Helderberg mountains, or in 

 Schoharie. 



The T. elongatus of the shaly limestone of the Lower Helderberg is known 

 to the author in many localities in the vicinity of Schoharie and the Helderberg 

 mountains, and has been recognized in the extension of that formation as far 

 south as New Jersey. 



The T. incurvus of Shumard, referred by its author to the same geological 

 age as above, seems to be unknown beyond the locality originally cited. 



