330 The American Geologist. November, 1905 
TAYLOR, THOMAS U. 
The water powers of Texas. Wat. Sup. Ir. Pap., 105, pp. 116, 
pis. 17, 1905. 
ULRICH, E. O. (See BAIN, H. F.) 
WEED, W. H. 
Notes on certain hot springs of the southern United States. 
(Wat. Sup. Ir. Pap., 145, pp. 185-206, 1905.) 
WRIGHT, F. E. 
Determining of the optical character of birefracting minerals. 
(Am. Jour. Sci., vol. 22, pp. 285-296, October, 1905.) 
CORRESPONDENCE 
Two Carboniferous G h:\era. — I notice that two generic names 
appear to be in use for Carboniferous fossils (c f. Weller, Bibl. In- 
dex, N. Am. Carb. Invert.) are homonyms, and untenable. 
(1) Microdon, Conrad, 1842 (Mollusca) ; not Microdot!, Meigen, 
1803. The name Cypricardella, Hall, is available. The species 
(following Weller) will stand as Cypricardella bellistriata (Conrad), 
C. connata (W i cott), C. elliptica ( ^hitfield), C. eximia M Her & 
Uurley C. gorbyi Miller, C. nucleata Hall, C. ohlonga Hall, C 
quadrata White & Whitfield C. reservata (Hall), C svbelliptica 
Hall. 
(2) Prest wichia. Woodward, 1867 (Crustacea) ; not Prestwichia, 
Lubbock, 1SG3. The name Euproops, Meek, is available for this 
genus. The species are E. colletti White, E. danae (M. & W.), 
aud E. longispina Packard. 
Goniodon, Herrick, 1888 (Mollusca), would be rejected by those 
who rejected Calamodon because of Calamodus (of Palmer, Index 
Generum mammalium, p. 151), as Goniodus, in fishes, is of course 
much earlier. This, however, is an extreme view, hardly likely 
to prevail. In the Index zoologicus Herrick's Goniodon is omitted, 
but there is cited a Goniodon, Perrier, in Echinoderms, without 
date, (c f. also Gregory, in Bather, Treatise on Zoology, part iii, p. 
253.) T. D A. Oockerlll. 
University of Colorado, Boulder, Colo. 
