200 PALAEONTOLOGY OF NEW YORK. 



diameter a little more than 1 mm. ; the apertures immediately adjacent are 

 slightly larger than those on other portions of the frond. 



This species, in its manner of growth and general appearance, is similar to 

 Fistulipora utriculus, of Rominger, but the apertures arc circular, while in that 

 species they are decidedly trilobate ; the manner of growth is similar to that of 

 Lichenalia cHvulata, of the Upper Helderberg group, but the apertures are much 

 larger and more closely disposed, the denticulations are much less conspic- 

 uous, and the peristomes are equally elevated ; the surface resembles that of 

 F. interaspera, but the manner of growth is diiferent, there is no depression 

 at the centre of the monticules, the denticulations are much less prominent, 

 and there are no interapertural pits : from F. constricta it is distinguished by 

 its manner of growth, its less prominent monticules, the flattened or gently 

 convex interapertural space, and the absence of mesopores ; the size of the 

 cell apertures and strength of denticulations are about the same in both species ; 

 from F. unilinea it is distinguished by its manner of growth, less prominent 

 monticules, smaller and more distant cell apertures, the absence of mesopores, 

 and the somewhat stronger denticulations ; from Lichenalia cornuta by the 

 manner of growth, larger and more distant cell apertures, and the much less 

 prominent denticulations : from Lichenalia substellata, of the Upper Helderberg 

 group, by the manner of growth, the thin and equally elevated peristomes, and 

 the granulose surface. 



Formation and locality. Hamilton group. West Williams, Ontario. 



Lichenalia colliculata. 



KOT KiaUKBD. 



Lichenalia colliculata, Hall. Trans. Albany Institute, Vol. x, p. 184. 1881. 

 " Report of State Geolojfist for 1883, p. 36. 1884. 



ZoARiUM consisting of free or incrusting lamellate expansions, or of masses 

 formed by the accretion of successive layers of growth ; epitheca strongly 

 wrinkled concentrically, frequently contorted. Cells tubular, cylindrical, 

 oblique or rectangular to the surface ; septa thin, in some cells moderately 



