H. 8. Williams—Fauna of the Chemung Group. 97 
Art. VIIL.—On a remarkable Fauna at the base of the Chemung 
Group in New York; by Henry S. WituiaMs, Pu.D., Cor- 
nell University. 
More than a year ago the writer discovered, at the base of 
the Chemung Group at Ithaca, N. Y., two species of Brachio- 
pods, which were hitherto regarded as peculiar to more western 
deposits, and a different geological horizon in America. These 
are a species of Productus described by Professor Hall as P. 
dissimilis (Iowa Geol. Rep., vol. i, Pt. II, p. 497), (entirely dis- 
unct from P. dissimalis of DeKoninck), and the form of Rhyn- 
chonella referred to Martin’s species, R. pugnus, by Meek, in 
the Illinois Geological Report, iii, p. 400. Both species are 
decidedly Carboniferous in aspect. Their lowest range in the 
West is in beds referred to the Kinderhook group of Meek and 
g akon, and to the Chemung, and to the Hamilton groups of 
€ ast. 
examined a few miles south of Canandaigua Lake, at High- 
point, Naples, N. Y., containing Productus dissimilis, varietally 
the species of which are almost all different from the normal 
Species of the New York Chemung fauna. 
he author is indebted to the kindness of Professor J. M. 
Clarke, of. Northampton, Mass., and Mr. D. D. Luther, of 
Naples, N. Y., for the discovery of these Naples beds. Recent 
examination of the material there collected reveals a fauna of 
More than ordinary interest. 
he Ithaca rocks under consideration are, stratigraphically, 
about five hundred and fifty feet above the top of the Genesee 
Slate, near the head of Cayuga lake. 4 
n this section the Portage rocks are about three hundre 
feet thick. e Naples rocks are near the summit of an abrupt 
hill, called High-point, and lie about twelve hundred feet above 
a ighest Genesee slate of that meridian, the dip being very 
slight, 
he High-point fauna is in a calcareous stratum, of — 
extent, in the midst of brownish gray sandstones and shales. 
he stratum is made up of a mass of Crinoid stem in 
. Shells, mainly Brachiopods, corals and Bryozoa, and wha 
*Ppear to be pebbles of a soft greenish shale. wast 
e following species have been identified by the author: 
