BIRDSEYE LIMESTONE. S9 



Fig. 1. A fragment of rock, showing several stems of this fossil with their anastomosing branches. 



Fig. 1 a. A similar vertical section where the stems have been divided, showing that they were origin- 

 ally hollow. 



Fig. I b. A bulb of stony matter, embraced by the stems or rootlets of this fossil. The stems apparently 

 proceed from such a bulb or root, as the radicles converge below, and diverge above, as 

 represented in the figure. 



Fig. 1 c. A horizontal section, presenting the ends of several stems, most of which are less than the 

 ordinary size. The rock is discolored for some distance around these stems, as if deprived of 

 its coloring matter by the carbonaceous character of the fossil. 



Fig. \ d. A horizontal section of stems larger than the usual size. These stems are cellular, with apparent 

 longitudinal dissepiments in two of the four presented in the figure. 



Fig. 1 e. A horizontal or transverse section of the stems, showing a concretionary arrangement of the 

 calcareous matter around them, which, on weathering, presents the appearance here re- 

 presented. This concretionary arrangement evidently took place during the deposition of the 

 calcareous matter and the growth of the plant, and appears to have constantly formed a little 

 eminence around the stem during the progress of the deposition. 



Position and locality. Throughout the Birdseye limestone, in various localities along the 

 Mohawk valley ; near Amsterdam ; Fort-Plain ; St. Johnsville ; Canajoharie, &c. 



{State Collection.) 



65. 2. PHYTOPSIS CELLULOSUM (n. *p.). 



Pl. IX. Figs. 1, 1 a, ft, c, d. 



Stems subcylindrical or compressed, diverging from a centre or root, procumbent or 

 ascending, branching ; branches irregularly anastomosing, forming a close strong network; 

 crust or covering thin ; substance cellular ; cells oblong, quadrangular or stellate. 



The difference in the structure presented in these figures, appears to be due, in a great 

 measure, to the direction of the section. A longitudinal section of a stem presents a simple 

 fibrous structure, with more or less distant interlacing transverse fibres, forming oblong or 

 quadrangular cells, as in part of 1 a, \h and 1 c. In oblique sections of the stem, square 

 or rhombohedral cells are presented, as in part of 1 a ; while in others, these cells present 

 a cruciform or stellate appearance, as in 1 d. Almost innumerable varieties of structure are 

 presented by the surfaces of weathered specimens, where sections of stems in every possible 

 direction, as well as in all stages of preservation, are prtesented. The form of mineralization, 

 varying from calcareous through all stages to perfectly siliceous, produces also some variety 

 of appearance in the fossil. The base of an individual, as fig. 1, is rarely seen, and only 

 where the matter of the rock is argillaceous. The portion represented is a small part only 

 of an individual ; for the branching and diverging stems extend at least several feet, and 

 we know not how much farther. 



While the first species appears to be the prevailing form in the Mohawk valley and some 

 other parts of the State, the latter species prevails almost exclusively in the valley of the 

 Black river and in Canada. The two are usually confounded, but their mode of growth and 

 their internal structure are suflicient to distinguish them. When crystallized, however, and 



