96 



PALXONTOLOOT OF .NEW-YORI. 



one, this inierior cast often becomes the most conspicuous feature, owing to the nature of 

 the materiiil in which it is enclosed, and the conditions attending its conservation. It is evident, 

 therefore, tJiui the Genera Actixoceras and Oblnoccras can not both be retained, unless 

 AcTisocERAS can be shown to relate to some other fossil than that to which it was originally 

 applied. It is true this name has priority over Ormoceras, but being founded in an erroneous 

 opinion of a fossil drawn from a figure, I have preferred to retain the latter name ; since 

 it is founded on a character belonging to the fossil, and not to a peculiarity exhibited in the 

 cast*. 



Position and locality. All the specimens of this species known to me have been collected 

 near Reynale's basin, Niagara county, from the lower part of the group. ,stau CoIIkIwh.) 



491. 28. ORTHOCF.RAS VIRGULATl'M (n. ip.). 



Pl. XXIX. Fig. 2 a, b, e. 



Slender, cylmdrical, gradually tapering ; siphunole sub-central ; surface marked by small 

 round pits or punctures. 



The subtance of the fossil is converted into a kind of chalcedony, and the shell is silicitied. 

 The punctures on the surface are probably not original markings of the shell, but due to 

 weathering and the peculiar arrangement of the siliceous particles. In another specimen, these 

 puncta are not preserved. 



Fig. 2 a. A. small fragmeni preserving the shell. 



Fig. 2 4. A section of the last. 



Fig. 2 c. A silicified fragpraent broken through the centre longitudinally, except the lower part. 



The greater convesity of the septum shown in this figure, over that in fig. 2 a, is 



owing to lateral pressure. 



Position and locality. In the lower siliceous limestone of the group, associated with the 

 preceding species, at Reynale's basin, and also at Lockport, Niagara county. 



492. 29. ORTHOCERAS ANNTLATUM ? 



Pl. XXIX. Fig. 3. 



Reference, Orthoceras annulatxim, Sowerbt, Min. Concbology, t. 133. See description, etc. 



under Orthocerata of the Niagara group. 



The fragment figured does not appear separable, by any specific distinction, from the species 

 in the Niagara group which is illustrated on Plate 64. It is much compressed, so that the 



*I should not omit to state here that I bare this moment had an opportunitr of seeing Mi. M'Cot's obsen-aiions 

 on the same subject, in his Synopsis of the Carboniferous Fossils cf Ireland, which work was uakaown to me except 

 bj name when I published my previous volume. 



