1895. | NEW YORK ACADEMY OF SCIENCES. 89 
Period of clear seas which furnished quantities of finely com- 
MMLC C Ce OSLES S01 3.02 b's BNO TPIER eed, Sokol. S ... 20 feet. 
Middle: Thin bedded, alternating, shaly and purer, dark col- 
ored limestone, frequently nodular or lenticular. 
Period of oscillating land level and consequent variability of 
deposition, extending through a long period of time. Lower 
portion particularly impure and generally encrinal, increasing 
in purity in the higher layers. Fossils chiefly fragmentary. 
316 feet. 
Lower: Not seen at Trenton Falls; found at Rathbone 
Brook, (B) 34 miles below Poland. Thin bedded, but more dis- 
tinctly marked zones than at Trenton Falls. Light colored in 
general and frequently sandy. Abundant Prasopora. Most re- 
mains fragmentary. Correspondence with above not yet deter- 
mined. 
Buiack River LIMEsTonEe.—First seen at the locality (A) 
three miles south of Poland. Impure, heavy bedded. Fossils 
numerous and well preserved................ 11 feet, 9 inches. 
BirpseyeE Limestone. — Heavy bedded, non-fossiliferous, 
dove colored, dolomitic limestone .......2.......... 9) ft; 6) in. 
Cuazy limestone not found, and evidently not deposited. 
CaLcirERous: Heavy bedded, dolomitic, non-fossiliferous. 
Underlies the Birdseye at the locality cited............. 8 feet. 
PuysicaAL FEATURES. 
These have been noted by Vanuxem, in the report for 1842, 
on pages 51 to 54, and are worthy of note. 
The creek undoubtedly follows a more or less strongly de- 
veloped series of north and south joint planes, and at Sherman 
Falls, shown in plate II, has come in contact with a series of 
joints at right angles to the former, as well shown in the wood 
eut by R. C. Taylor, on page 52 of the report referred to. The 
gorge at this point is crossed by a perpendicular wall, extend- 
ing from the eastern bank (shown on the right-hand side of the 
illustration in this paper) nearly to the western bank. <A por- 
tion of the creek at high water still falls over this wall on the 
right-hand side and centre, as shown; the larger body, however, 
pours into a second joint lying some twenty or thirty feet be- 
hind, and is in process of widening this latter crevice from west 
to east, so that eventually the original face of the fall will be- 
come entirely detached and the fall be obscured behind its 
rocky screen. 
At the top of the lower portion and between it and the upper 
portion of the High Fall a layer contorted into semi-circular pli- 
