DESCRIPTIONS OF GENERA AND SPECIES. 
DENDROPHYCUS TRIASSICUS, N. sp. 
Pl. XXI, Figs. 1, 2. 
In the Geology of Pennsylvania, by H. D. Rogers (vol. 2, Pl. XXIID), 
is represented a fossil plant which is designated as an ‘“‘algoid resembling a 
Desmarestia.” This is fossilized in the red shale of the ‘‘Umbral,” a part of 
the Lower Carboniferous formation in northern Pennsylvania. The fossil 
consists of a number of branching stems from which are thrown off slender 
dichotomous branches from either side, and these branches, cylindrical like 
the stems, support numerous opposite or alternate simple branchlets. No 
reference to this plant is made in the text, but it is evident that it is what it 
is represented to be, a sea-weed, though its affinities with the living algee 
may be a matter of doubt. 
In the Report of the Second Geological Survey of Pennsylvania (vol.3), 
Coal Flora, by Leo Lesquereux, a figure is given (Pl. I) of what is appar- 
ently the same plant as that figured by Rogers. This is briefly described* 
under the name Dendrophycus Desorv. It is said to occur in the red shale 
below Pottsville, and also abundantly in the bluffs of the Susquehanna 
above Pittston. 
Splendid specimens of this plant are reported by Mr. Lesquereux® as 
occurring ‘near Davenport, Iowa, in a bed of clay and hardened sand- 
rock, traversing like a dike the Corniferous limestone overlaid by the Ham- 
ilton group.” In his deseription of this plant Mr. Lesquereux says: 
The roots or radicular appendages, * * * are apparently cyiindrical or tubu- 
lous, * * * often branching at right angles, three or four mm. in diameter, of 
1 Op. cit., pp. 699, 700, 2Op. cit., p. 701, 
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