Senecnii. 
Rcz'ic:^' of Recent (icoloiiical Literature. 325 
The r<icks sliown u|).iii tlii^ mai) all holonp; to the late r)c\(jiiic and 
they have heen classed in tlu- tullnuiiiK divisions : 
\ Chemung sandstone and -hale 
Chantauquan ■ ,, _ .,, , , 
' J Prattsvdlc shale 
High Point Sandstone 
West Hill il:igs and shale 
Grimes sandstone 
1 latch shale and flags 
J Rhinestreet black shale 
] Parrish 'limestone 
Cashaqua shale 
I West River shale 
I Gennndewa limestone 
I Genesee shale 
The distinction between (jenesee shale and West River shale (the up- 
per division of the Genesee shale series) which obtains further west is 
still maintained in this region while the Middlesex shale, a distinct 
stratigraphic element, at the base of the Cashaqua shale in the Naples 
quadrangle is no longer recognizable in the Watkins quadrangle. Both 
the Parrish limestone and the Rhinestreet shale have been traced as far 
as Seneca lake, but are not known east of that meridian. 
In the Hatch shales and flags which attain a thickness of 440 feet, 
a distinct o.sciilation between the areas of the western or Naples fauna 
and the eastern or Ithaca fauna has been observed. 
The High Point sandstone has in this quadrangle furnished cal- 
careous lenses with their characteristic brachiopod fauna. 
The Prattsburg shale, a name proposed in the explanation of the 
Naples sheet for the eastern extension of the Wiscoj-- shale in which a 
typical Chemung brachiopod fauna appears, is strongly developed in 
the Watkins quadrangle and has furnished a large fauna. 
In order to arrive at the precise use of the term "Chemung" which 
has in late years been more or less identified with the horizon of Spirifcr 
disjunctus, the authors have found it necessary to return to Hall's 
original employment of the name, since in this eastern region Spirifer 
disjunctus does not appear until the period of Chemung deposition is 
well nigh over. The region here considered is that from which the 
original definition of the term was derived. This typical Chemung 
attains in the Elmira quadrangle a thickness of 800 feet. 
The aggregate thickness of the Upper Devonic formations repre- 
sented on the sheet is approximately 2244 feet. There are some not- 
able undulations of the strata which present striking northern dips. 
Geology and Water Resources of Part of the Lozver James River Val- 
ley, South Dakota. By J. E. Todd and C. IM. H.\ll. U. S. Geol. 
Survey, Water Supply and Irrigation Paper No. 90. Pages 47, with 
23 plates. 1904. 
The area here described, partly 'from field work by the late Prof. 
Charles ^r. Hall, includes the Alexandria. Mitchell, Huron, and De 
