28 NEW YORK STATE MUSEUM 



early as the Anticosti group of Anticosti ; it is common in the Lockport 

 dolomite of New York, and is reported from the same horizon in Ontario 

 (Thorold) ; in Wisconsin it ranges from the Mayville beds, through the 

 coral and Racine beds into the Guelph horizon. 



HBLIOPHTIXUM Hall. 1849 



Heliophyllum sp. indet. 



Plate 1, fig. 4, 5. 



A single internal cast of a small calyx found in the Guelph of Roches- 

 ter shows distinctly the impression of the denticulations on the septa, which 

 in the present state of our knowledge are regarded as characteristic of 

 Heliophyllum. Though a considerable number of Siluric species have been 

 referred to this genus, the specimen in hand is not sufficiently complete for 

 identification. 



TABULATA 



FAVOSITES Lamarck. 1816 



Coral stocks of Favosites belong to the most common fossils of the 

 Guelph dolomite. The different coralla show considerable variation, indi- 

 cating the presence of several species. 



Favosites niagarensis Hall 



Favosites niagarensis Hall, Paleontology of New York. 1852. 2:125, pi. 



34A bis, fig. 4a-h 

 Favosites gothlandica Whiteaves (in part), Paleozoic Fossils. 1895. v. 3, 



pt 2, p. 50 

 Favosites niagarensis Lambe, Contrib. Canadian Paleontology. 1 899. v. 4, 



pt i, p. 71 



This is one of the commonest of the species in the white chert nodules 

 at Rochester and the upper Guelph of Oak Orchard creek. The specimens 

 are for the most part subspheric, attain the size of the fist and are composed 

 of corallites which are seldom larger than 2 mm in diameter, and average 

 considerably less, specially in immature growth. The tabulae are regular 

 and flat, but vary in the intervals between them in different specimens, from 

 .3 mm in one to 1.5 mm. On account of the incrustation of thickened walls, 



