REPORT, Ob DHE DIRECTOR, 1922 T49 
ES STRATIGRAPHY OF THE CHEMUNG GROUP IN 
WESTERN NEW YORK 
BY GEORGE H. CHADWICK 
Two summers have been spent in field work on the upper 
Devonian of western New York, one (1918) for the Dominion 
Natural Gas Co., by whose liberality full publication is permitted, 
the other (1922) for the Museum, together with intervening sorties 
at the writer’s own charge. The results are here briefly summarized. 
The field is a large one and much remains to be done. The most 
puzzling questions yet outstanding exist chiefly because of either 
lack of topographic maps or difficulty in finding outcrops, both of 
which time will remedy. The problem is everywhere primarily one 
of geometry, which no amount of paleontologic acumen can over- 
come, since the fauna varies deceptively with the sediments. 
The highest Portage member on Lake Erie is the Hanover 
(formerly Silver Creek) shale,? which has been traced continuously? 
into the Wiscoy shale* of the Genesee valley. The Chemung group 
commences with the Dunkirk black shale.t This extends from Van 
Buren Point, on Lake Erie, by way of Walnut creek ravine,* Ver- 
sailles, North Collins,* Boston, Colden and Pipe creek glen,’ with 
constantly augmenting thickness, to Holland,® where it is over 160 
feet thick. Two characteristic (and unlike) septarium zones 
divide it into three members, throughout this distance, the upper of 
which three divisions was included by Luther’ in his overlying 
Portland shales. Beyond Holland, past Hunter’s creek to the Java 
Village ravine,” and above Varysburg,® sandstone layers increase 
rapidly in number and thickness in the black shale. In the Genesee 
valley, on Wiscoy creek’® and elsewhere, these sandstones occupy 
much of the lower half of the Dunkirk and include the fossiliferous 
"ING WW, Stare Minis, IB Go), ime, 12, jo, mae, ING NE Stee IMEC Tally 1G) 
(2d ed), p. 76 
_ Bul. Geol. Soc. Am. 30, p. 157. 
*16th Rep’t N. Y. State eet, . BA, iBlaxnclolk, 7S, Do. OB, INo Wo Stee 
Mus. Bul. 60, p. 1008. N. Y. State Nee Bul. 128, p. 64. 
*N. Y. State Mus. Bul. 60, p. 2025 
°N. Y. State Mus. Bul. to, ai LXXXIT (name misspelled). 
“15th Rep’t N. Y. State Geol., p. 321. 
*N. Y. State Mus. Bul. 60, fis. a (DL, WOvAS\S thes, 10}, 0, OARS), 
“Wh, S, Gaol, Swan. IB, 4, je “oaSo, IN We Steltie IWhtig, TB(Glloley is) Gy, 
210-08. N.Y. State Mus. Bul. 60) p. 1017. 
*"N. Y. State Mus. Bul. 60, p. tora. N. Y. State Mus. Bul. 172, p. 28-30 
and map. 
saN Ye State’ Mus, Bul) 60, p: 1018) N.Y. State Mus. Bul: 118, p. 67-68: 
