6 



PAL^ONTOLOSY OF NEW-YOHK. 



383. 2. ARTHROPHYCUS 



Pl. ir. Fig. 2. 



This species presents large rug-ose expansions, which are curved into irregular shapes. The 

 substance appears as if composed of a number of flattened stems, coalescing at their edges. 



From the position in which this form is usually found, it appears not unlikely to have been 

 the root of the preceding species. Its entire characters, however, have not been fully determined. 



Position and locality. This form occurs usually in the thicker layers, associated with the 

 preceding species at Medina, Orleans county, and at Lockport, Niagara county. 



{State Collection.) 



384. 2. SCOLITHUS VERTICALIS {n. sp.). 



Pl. HI. Fig. 3. 



Plant composed of smooth round stems, which penetrate the strata vertically. 



This species is smaller than the one in the Potsdam sandstone, though resembling it in its 

 general characters. It penetrates the more firm and arenaceous strata, and has not been found 

 associated with the preceding species. 



Position and locality. In the thick-bedded sandstone of Monroe county. {State Collection.) 



385. 6. PAL^OPHYCUS TORTUOSUS (n. sp.). 



Pl. III. Figs. 2 a, b. 



Stems or branches rounded, tortuous, frequently bifurcating ; surface smooth and glossy. 



This species is a branching one, though it has been impossible to procure it in a condition 

 to give a full representation of its form. The branches are often twisted or bent in zigzag forms, 

 probably from pressure. It usually occurs in the thickbedded portions of the rock ; and being 

 replaced by soft argillaceous matter, it has a slightly different and more brilliant color. 



Position and locality. This species occurs in the central or lower part of the rock, about 

 the mouth of the Genesee river, and at the Irondequoit bay. It likewise occurs in other parts of 

 the rock, but is never abundant at any locality. {State Collection.) 



386. 1. DICTUOLITES BECKII. 



Pi,. II. Fig. 1. 



Lithodictuon beckii. Cowhad, Annual Geol. Reports of 1837, p. 167, note. 

 Dictuolites beckii. Annual Report on Palaeontology, 1838, p. 113. 



' — — Hall, Geol. Report of the Fourth District, pag. 48, pl. 1, fig. 1. 



A body composed of numerous strong stems or branches joined in an irregularly reticulated 

 manner ; branches furnished on each side with lateral rootlets, which extend from the elevated 

 branches into the surrounding stone. 



