REPORT OF THE STATE PALEONTOLOGIST 1902 893 



The Tully pyrite contains a fauna so diminutive that it es- 

 capes ordinary observation; so simple that it seems like a 

 group of young forms; and so unlike the usual species of the 

 limestone that without definite knowledge of its horizon it 

 would be difficult to locate its stratigraphic position. Few of 

 the specimens are over 2 mm in diameter, but are adults. The 

 fauna is rich, including Crustacea, Cephalopoda, Lamellibranch- 

 iata, Gastropoda, Brachiopoda, and Crinoidea; corals failing 

 entirely. 



This fauna was first noticed by J. M. Clarke in 1885, 1 who 

 recorded 12 species, describing 11 of them as new; and sug- 

 gested that there was abundant opportunity to enlarge the 

 fauna. Two years ago, Dr Clarke placed some of the pyrite 

 matrix from Canandaigua lake in my hands, and later more 

 from other localities. In all the regions represented by this 

 material, life was abundant, a cubic inch of rock rarely furnish- 

 ing less than two or three fossils; but, on account of the small 

 size, they are difficult to find and more difficult to remove, as 

 the matrix is extremely hard and tenacious. 2 



So far as we have made it out, the fauna consists of 51 species, 3 

 mostly less than 2 mm in diameter. These are distributed as 

 follows: 40 from Canandaigua lake, 33 from the Livonia salt 

 shaft (at a depth of 280 feet), 27 from Greigsville, 25 from Little 

 Beard's creek near Moscow, and 19 from near the Delaware, 

 Lackawanna & Western Railroad at Moscow N. Y. The greater 

 number from the first two localities is due partly to the fact 

 that more rock from these was broken up, and partly because 

 they are richer in specimens. The shells of most of the Brachio- 

 poda have a distinctly Prehamilton appearance, doubtless due 

 in some measure to their arrested condition of growth. Many 

 of the gastropods and cephalopoda have also such an aspect; 

 but along with such shells are occasional larger representatives, 



1 U. S. Geol. Sur. Bui. 16. 1885. p. 28. 



2 The only successful method devised for removing the fossils is to roast the 

 pyrite some time over a blue flame, and then plunge in cold water. Without 

 roasting, the matrix will not come away from the fossils, but breaks through 

 them. After roasting, however, the pyrite cleaves away, and with a lens the 

 tiny forms may be found. 



3 Two more species were found, but lost in trying to prepare them more com- 

 pletely for drawing. 



