17 ALGiE. 



milleri; P. gracilis; divaricatus are described by Lesq. in Coal 

 Flora, 1880, pp. 10, 11, 12, as found in iron stone nodules in a 

 bed of clay over coal L of the Indiana coal field; Asterophy- 

 Gus (starry seaweed) coxii, from sandstone beds in the Upper 

 and Lower Coal measures on the Wabash ; Aster opliyciis sim- 

 plex^ from irony clay over the conglomerate in Beaver Co.,, 

 Fa. See Coal Flora, Plate B, figs. 7, 8 ; Conostychus however 

 is too much like the sponges to be accepted without hesitation 

 as a plant. 



Dendrophycus desorii is another form of the early coal age. 

 Coal Flora, p. 700. (This Dawson calls a rill- marking; Geol. 

 Hist. Plants, 1888, p. 33.) Dictyophyton (net plant) of the 

 Chemung age ( VIII g) is placed by Lesquereux among the sea 

 weeds. The much earlier Silurian sea weeds, so called^ like 

 Bilohites^ Palmochorda^ Palwophytus^ licrophycus^ Rutliro- 

 trephis^ Aster ophycus^ Rusophycus^ Arthrophyciis^ Crusiana^ 

 Eophyton^ are now pretty generally accepted as worm hurrows^ 

 worm tracks^ worm dung^ and the various kinds of marks left 

 by various kinds of most ancient (as well as modern living) 

 animals on the shallow sea bottom ; as proved by Nathorst of 

 Sweden, and Dawson of Canada. See Geol. Hist of Plants, 

 Dawson, NeAv York, 1888, p. 26. Such are now called Pro- 

 tichnites^ (See Protichnites lineatus) ; liiisicJmites^ (See 

 E,usiclinites acadicus); Nereites^ Planulites^ Phabdiclinites^ 

 etc. Shrinkage cracks have also often been mistaken for fossil 

 sea weeds. But this idea, carried too far under the inspiration 

 of Nathorst's admirable researches, has produced a reaction. 

 The best paloeontologists express the opinion that some of the 

 Cambrian and Silurian forms must be accepted as true fossil 

 fucoids; and that sea-plant life must have long preceded land- 

 plant life. 



In the collections of the Survey are good specimens of algm 

 from Venango County: see Report O, No. 2912, in Sandy 

 shale, Milltown hill, 3 m. e. of Pleasantville ; 2945, in gray 

 sandstone, Henderson farm ; 2951, on green sand shale, Pooker 

 farm, Pithole ; 2943, in gray sandstone, McGee run ; 3268, in 

 Pocono X, sandstone, e. end. Oil City bridge. From McKean 

 Co., 3635, and 3657 on Chemung^ VIII g. green shale, hill e. of 

 DeGolier. 



