BUFFALO SOCIETY OF NATURAL SCIENCES 97 



an association of finely preserved seaweeds, the eurypterids herewith 

 described, and the following graptolites: Dicellograptus gurleyi Lap- 

 worth, Climacograptus bicornis Hall, Climacograptus bicornis var. 

 peltifer Lapworth, Cryptograptus tricornis (Carruthers), the first three 

 forms in great abundance. This graptolite association is one of 

 undoubted Normanskill age. The seaweeds occur in large perfect 

 fronds and are of the same type as those in the Schenectady shale. 

 The eurypterids also are strikingly similar to those from the Schenec- 

 tady beds" (39, 411, 412). 



The eurypterid remains are very fragmentary, in fact, they are 

 so incomplete that generic determinations are only provisional, there 

 being but a few carapaces and fragmentary abdomina with a small 

 number of legs and telsons rarely attached. Five genera are thought 

 to be represented: Eurypterus, Eusarcus, Dolichopterus, Stylonurus 

 by one species each, and Pterygotus by two species, though one of 

 these may be a Eusarcus. 



The physical characteristics of the Schenectady beds are closely 

 similar to those of the Normanskill beds. Both consist of heavy 

 bedded sandstones, dark in color, but highly siliceous, alternating 

 with black shales. The sandstones are compact enough to be quarried 

 for building and paving purposes. Both the shales, and bluestones 

 change westward into shales, and eastward become very coarse. In 

 the Normanskill beds pebble layers alternate with the sandstones, 

 while in both formations mud cracks are found in the shales and 

 subsolifluction contortions in the sandstones, structures which show 

 a slumping motion of the sands along the shore (Berckhemer, 21). 

 The sandstones contain eurypterid and plant remains, the latter 

 identified as Sphenophycus latifolius, and having a remarkably thick 

 carbonaceous test which is so high in carbon that it will burn. In 

 the shales occur the graptolites and eurypterids, the latter not being 

 so abundant as in the sandstones, but exhibiting better preservation. 



The sediments of both the Normanskill and the Schenectady were 

 undoubtedly derived from the east as the following facts indicate: 

 (1) Coarse materials, conglomerates and sandstones with intercalated 

 shales in east along Schenectady-Catskill line, passing laterally into 

 fine black shales westward in the Mohawk Valley; (2) deposits thicker 

 and coarser in east than in west; (3) evidences of shore conditions in 

 sun-cracks, wave marks, and subsolifluction, in east, of conditions in 

 quieter water farther from shore in the fine black shales westward. 

 Appal achia was the only large land area to the east from which 



