566 NEW YORK STATE MUSEUM 



6 G. sp. nov. cc 



7 Coenograptid gen. nov. et sp. nov. c 



8 Tetragraptus serra Brong. small mut. c 



9 T. bigsbyi Hall small mut. c 



10 T. fruticosus Hall small mut. cc 



11 T. pendens Elles rr 



12 Didymograptus cf. similis Hall r 



13 D. bifidus Hall cc 



14 Phyllograptus typus Hall c 



15 P. anna Hall cc 



16 P. angustifolius Hall c 



17 Nemagraptus sp. r 



18 Thamnograptus anna Hall c 



19 Lingula quebecensis Billings rr 



20 Small indet. brachiopods cc 

 To this zone belong a-lso the beds j, k, 1, m and n, hard greenish 



silicious beds, sandy shales and limestones. Bed j bears, on 

 black shaly partings, Didymograptus bifidus, the 

 most characteristic form of this zone. The thin graptolite bed 

 4 in bed 1 also furnished this species and a few poorly preserved 

 fragments of some of the other forms. 



Graptolite oed 5 



Under this notation have been united the numerous shaly 

 partings between the heavy banks of greenish gray, extremely 

 hard, silicious rock which is exposed, with a thickness of 52 

 feet, in the quarry at the east end of the continuous section 

 (stratum o; the shaly partings are denoted on the diagram by 

 the letter p). Most of these partings are covered to the exclu- 

 sion of other species, with the rhabdosomes of the species 

 Phyllograptus typus, Ph. ilicifolius (large muta- 

 tion) and Ph. anna. The largest specimens of Phyllo- 

 graptus typus occur however in a layer at the base of 

 graptolite bed 3. The full list of the species observed in the 

 quarry is : 



1 Tetragraptus quadribrachiatus HaU c 



2 T. serra Brong. r 



