38 pal5:ont0logy of new-york. 



Genus PHYTOPSIS. 



[Greek, (purov, a plant, and o^-i?, resemblance.] 



Stems cylindrical or subcylindrical, straight or flexuous, erector procumbent, branched; 

 branches diverging and anastomosing; structure cellular, consisting of thin laminae with 

 transverse divisions ; other portions presenting a reticulated structure. 



64. 1. PHYTOPSIS TUBULOSUM («. 6^.) . 



Pl. VIII. Figs. 1, a, b, c, </, e. 

 Fucoides demissus. Emmons, Geol. Report, pp. 109, HO, 383 & 384.* 



Stems subcylindrical, sometimes obtusely angular or compressed, branched ; branches 

 inosculating obliquely, or in an ascending direction ; external covering thin, calcareous? ; 

 centre usually filled with softer materials, or crystallized. 



This very remarkable fossil forms one of the most prominent features of the Birdseye 

 limestone along the Mohawk valley. In vertical sections of the strata, it presents the 

 appearance represented in figs. 1 and 1 a. Where the rock is not too crystalline, the internal 

 substance of the fossil is argillaceous, and presents a contrast in color to the surrounding 

 rock. Tlie general direction of the stems is vertical ; but the anastomosing branches diverge 

 at all angles, uniting with the contiguous stems, thus forming a connection throughout the 

 mass for many feet in extent. 



Sometimes these tubes are filled with crystalline calcareous matter, and the surface of 

 the rock presents numerous crystalline points or round spots, and, in a vertical section, 

 lines of this crystalline matter, the structure of the fossil having been obliterated. This is 

 true in many parts of the Mohawk valley, and in the Black river valley, where tl\e other 

 species prevails. In Kentucky and Tennessee, this rock is marked by numerous crystalline 

 points and lines indicating the existence of this fossil, but I have never been able to detect 

 its structure in any specimens from these places. The species is known to us in its greatest 

 perfection along the Mohawk valley. 



Tiie figures on Plate VIII. present the usual aspect under which this fossil appears. 



• This fossil has usually been referred to the Fucoides demissus of Conr.^d ; but I regard it as by no means certain 

 that Mr. C. intended to apply this name to the fossil under consideration. In his report of 1838, he enumerated no 

 less than six new species of Fucoides in the lower strata, and it is therefore safer to describe under a new name, than 

 risk confounding with other species. 



Dr. Emmons has given illustrations of this fossil in his Report above quoted. Those on page 109 correspond with a 

 very common appearance of lliis fossil and the succeeding species (PI. ix.). I have not been able to discover specimens 

 showing the anastomosing of the connecting branches, as represented on page 110 of that report. The specimen figured 

 on page 3SI, fig. 3 (Emmons, Geol. Report), showing the structure of a coralline, doubtless ari.ses from a Favositet 

 or Chtctetcs, which has fixed its residence n])on one of these stems ; for it is unlike any structure I have been able to 

 detect, in the examination of several hundred specimens of the fossil in all stages of decay and exposure. 



