246 ^ NEW YORK STATE MUSEUM 



Rensselaeria aequiradiata (Conrad) 



One specimen is 25mm long and 15mm wide at the widest place 



which is anterior to the middle of the shell. The greatest thickness^ 



iimm, is posterior to the middle. Another one from the Lower 



Oriskany measures 23+mm by 15mm, the complete length could not 



be determined owing to the broken condition of the front of the 



shell. 



R. subglobosa Weller 



This shell was called by Dr S. T. Barrett,^ on the identification of 



Profes'sor Hall, Rensselaeria mutabilis Hall. But Dr 



Barrett explains that it is much larger than any known before. It 



differs from this, however, also in its surface markings and was 



hence made into a new species by Dr Weller.^ This is one of the 



most abundant shells of the Trilobite bed, and is nearly always well 



preserved. 



Megalanteris ovalis? Hall 



Two specimens were provisionally identified with this species; 

 both are internal molds of the pedicle valve and agree very closely 

 with the figures and description given by Hall.^ 



Atrypa reticularis (Linnaeus) 



Found only in the Coeymans, Becraft and Onondaga, the purely 

 calcareous formations ; it is quite abundant in each of these. 



Atrypina imbricata Hall 



Quite abundant in the Upper New Scotland but no specimen was 

 noticed in the Lower New Scotland. A large shell measured 9mm 

 by 9.5mm by 4.5mm in length, breadth and thickness respectively. 



Spirifer vanuxemi Hall 



One of the most abundant and constant shells in the Manlius. The 

 usual size of the brachial valve is 5mm by 8mm by 2mm in length. 



^Notes on the Lower Helderberg Rocks of Port Jervis, N. Y. Lye. Nat. 

 Hist. Ann. 1876. 11:290. 



'Gedl. Sur. N. J. 3:329, pl.42, fig.ii-i8. 



"Rensselaeria ovalis Hall. Pal. N. Y. 1859. 3 :458, pi. 106, fig.2a-l. 



