458 \ NEW YORK STATE MUSEUM 



weathers ash-white with a deHcate bluish tint. The peculiar plant- 

 like reticulation of Phytopsis tubulosa Hall is very 

 conspicuous in the rock at this locality since the former weathers 

 buflf whereas the matrix weathers nearly white. The vertical 

 columns are larger than in the rock of this horizon near Newport 

 and Littlefalls where they are quite small and composed of calcite, 

 while in the Birdseye of the lower Mohawk they are composed of 

 argillaceous or pyritiferous material. iWithin the limits of the ex- 

 posure, a small quarry, the limestone varies from 2 to 4 feet 

 in thickness, both dehmiting terranes being in place. The upper 

 surface of the subjacent Calciferous is uneven and hence the line 

 between it and the overlying Birdseye is very sharply drawn. 

 Above, the Birdseye seems to pass into the superjacent Black river 

 without any sharp line of demarcation. 



The following species were obtained from the Black river lime- 

 stone, C^: 



1 Monticulipora (Prasopora) lycoperdon Say (aa) 



Branched form 



2 Streptelasma comiculum Hall (c) 



3 Streptelasma profundum Hall? (r) 



4 Stictopora elegantula Hall i (r) 



5 Stictopora cf. ramosa Hall (r) 



6 Phytopsis tubulosum Hall? (r) 



7 Columnaria alveolata Goldfuss (c) 



8 Zygospira recurvirostra Hall (c) 



9 Plectambonites sericea (Sowerby) Hall and Clarke (r) 



10 Rafinesquina altemata (Con.) Hall and Clarke (c) 



1 1 Asaphus platycephalus Stokes (r) 



12 Hormoceras tenuifilum Hall (r) 



13 Crinoid segments 



The base of the Trenton stage in this section is 380 feet A. T. 

 and in the Quarry hill one and one half miles to the north the base 

 of the Trenton stage is 600 feet A. T. This gives a south dip of 

 1.47 feet a mile. By barometer the former point is 175 feet above 

 the level of the Mohawk and the latter 400 feet, which gives the dip 

 as 150 feet a mile to the south-southwest. 



Along the creek which empties into the canal one and three- 

 tenths miles due west of Crane's village station the following sec- 

 tion was measured (46E) : 



