PEIMORDIAL FOSSILS. 333 



PAL^OPHYCUS, sp. ? 

 Plate 1, tig. 1. 



Besides the foregoing species of Palceophjcus in the plant-beds at the 

 head of Eedwater Valley, there are layers covered in places with disjointed 

 and almost characterless stems or rootlets of various sizes, ranging from a 

 twentieth of an inch to those of nearly or quite one-fourth of an inch in 

 diameter, and of various lengths. Some of them are straight and ridged, as 

 though they had been hard cylindrical bodies ; while many are more or 

 less flexuous, and others have clavate terminations ; but among them there 

 are none preserving enough of form to characterize them as a species, or to 

 place them positively in any established genus of value ; we have therefore 

 represented them only, leaving them doubtfully under the above genus, but 

 without specific designation. Attention being thus directed to them may 

 lead others to collect and examine them still further, by which means some 

 light may be gained as to their nature and origin. 



Very similar forms are common on certain layers of the Clinton Group 

 of Oneida County, New York, where very similar conditions have existed ; 

 but so far as we are aware no positive determination has been reached as 

 to their exact nature Figures of these latter are given by Professor Hall 

 in Vol. II, Paleontology of New York, Plate 9, Fig. 4, and others of cor- 

 responding character are common on the Portage sandstones of Western 

 New York. 



INTCERT^ESEDES. 



AEENICOLITES, sp. ? 

 Plate 2, fig. 25. 



Some specimens of a hard white sandstone of the Potsdam Group, col- 

 lected near Warren Peaks, in the northern part of the Black Hills, are filled 

 with cylindrical perforations of an undetermined length, but measuring 

 about two inches on the specimen in hand, were supposed to represent 

 the existence of the genus Scolithus. The tubes are about one line in 

 diameter, but are slightly variable in this respect, and have a somewhat 

 rigid character, although by no means parallel to each other, and some- 



