296 Eeport of the State Geologist. 



coenosteum often develops little pits or conical depressions about 

 4 mm. apart, which are rather characteristic of the species. S, 

 foveolatum differs from jS. centrotum in its thick and dense 

 laminae, its low monticules and its conspicuous astrorhizse. 



Horizon. — Lower Pentamerus limestone. 



Locality. — Cedarville,]^.Y. 



Stbinoostroma mickoporum, sp. nov. 

 Plate VI, figure 7. 



Coenosteum massive, latilaminate, shape unknown, probably 

 spherical or subspherical. Surfaces parted along the latilaminae 

 are covered with numerous monticules, which are, however, of 

 small size. They are usually pierced by axial tubes and provided 

 with well-developed astrorhizae seldom visible on the lamellar 

 partings. In vertical sections the skeleton is seen to be composed 

 of persistent radial pillars and the customary concentric laminae. 

 Tangential sections show the laminae to have a finely porous 

 structure, the skeleton fiber being of the characteristic reticulated 

 tissue common to other Helderberg Syringostromas. Tangential 

 sections through the monticules show only the cut ends of the 

 astrorhizae. When the section lies in the lateral slope of a 

 monticule, the latter is seen to be provided with an extensively 

 spreading astrorhizal system. The thickness and density of the 

 lamina in S. foveolatum readily distinguishes it from this species 

 in microscopic examination. Furthermore, monticules are here 

 apparent, and there is no indication of a tendency to weather 

 into conical pits, as in S. foveolatum. 



Compared with S. centrotum^ the skeletal tissue is much finer, 

 and the monticules less numerous. 



Formation. — Lower Pentamerus limestone. 



Locality. — Cedarville, N. Y. 



Syringostroma Barretti, sp. nov. 

 Plate VII, figures 5, 6. 



Coenosteum large, hemispherical, spreading. Latilamina3 dis- 

 tinct, more or less labyrinthine toward the center, on the 

 periphery flowing in broad folds. They end abruptly on the 

 under side, and are attached directly without an epitheca. Lam- 

 inae parallel and gently flexuous. Astrorhizae not numerous, but 



