CLINTON GUOUr. 



S3 



ACEPHALA OF THE CLINTOxN GROUP. 



The species of Acephala of this group are comparatively few, and they form no very con- 

 spicuous palffiozoic feature of the strata. With the exception of a few localities, they are 

 extremely rare, and I have not yet seen a single species west of Rochester. The shales below 

 the iron ore bed in the eastern part of Wolcott have furnished more than all the other loca- 

 lities ; while one or two species are quite common farther eastward, in the non- calcareous 

 portions of the group. It is probable that other localities (were they accessible), between the 

 eastern part of Oneida county and Wayne county, would furnish a greater number of species 

 and individuals ; but this portion of the formation lies in a low, level tract of country, scarcely 

 accessible at all from natural exposures, and there are few artificial ones. We are warranted in 

 this inference from the fact that in New-Hartford and Kirkland we find several species in con- 

 siderable numbers, which are unknown in the localities in Wayne county, while these localities 

 furnish other species unknown in Oneida county. We infer, therefore, not only from these 

 facts, but from similar ones in relation to most of the Brachiopoda, that the species existing at 

 the period of this deposition were limited in their geographical extent, and consequently every 

 locality discovered will disclose new species. Those which we now present, therefore, can 

 not be regarded as a full exposition of these forms in the group ; and in the Acephala this 

 period is less perfectly represented than in the Brachiopoda, which have been collected from 

 a greater number of localities extending over a wider space. 



472. 6. AVICULA EMACERATA. 



Pl. XXVII. Fig. 1 a, b. 



Avicula emacerata. Conhad, Jour. Acad. Nat. Sci. Philadelphia, 1842, pagp. 241, pl. 12, fig. 15. 

 Avicula leptonota. Hall, Geol. Rep. 4th Dist. N. York, 184.3, pag. 76, fig-. 5. 

 For description, see ji. emacerata, Niag-ara g-roup. 



The specimens examined thus far present no real difference from the Niagara species, and 

 I have thought proper to unite the two. The specimen figured in the Geological Report (Fourth 

 District), has the form there represented ; but on a more careful examination, I am inclined to 

 believe that it is distorted by pressure. Other specimens in the same soft shale are evidently 

 distorted in a greater or less degree, scarcely any two individuals preser%-ing precisely the 

 same form. Those now figured from the Clinton group are scarcely at all distorted, and pre- 

 sent so many features in common with the species in the Niagara shale, that I have referred 

 them to the same. 



Position and localities. This species occurs in the ferruginous layers associated with the 

 ore beds in Kirkland, Oneida county ; also in the shaly layers at Blackstone's quarries, and in 

 the soft shales below the ore bed in Wolcott, Wayne county. {State Collection.) 



