Correspondence. 383 
Upham, Warren. 
Artesian wells in North and South Dakota. (Bull. Minn. Acad. 
Sci.. vol. 3, pp. 370-379- iSOi.) 
Warren, C. H. 
Mineralogical notes. (Am. Jour. Sci., vol. 11, pp. 369-373- May, 
1901.) 
Weeks, F. B. 
An occurrence of Tungsten ore in eastern Nevada. (21st Ann. Rep., 
U. S. Geo!. Sur., part vi. p. 319. 1901.) 
Weller, Stuart (H. B. Kummel and) 
Paleozoic limestones of the Kittatinny valley, New Jersey. (Bull. 
Geol. Soc. Am., vol. 12, pp. 147-162. Apr., 1901.) 
Whiteaves, J. F. 
Note on a supposed new species of Lytoceras, from the Cretaceous 
rocks of Denman island, in the strait of Georgia. (Ottawa Naturalist, 
vol. 15, pp. 31-32. Mar., icoi.) 
Winchell, N. H. 
The Geology of Minnesota, final report, vol. vi. Geological atlas, 
with synoptical descriptions, 89 plates. St. Paul, 1901. 
Woodworth, J. A. 
Original micaceoiis crosshanding of strata in current action. (Am. 
Geol., vol. 27, pp. 281-284. May, 1901.) 
Wortman, J. L. 
Studies of Eocene mammalia in the Marsh collection. Peabody mus- 
eum. (Am. Jour. Sci., vol. ir, pp. 333-348- ^lay, 1901.) 
CORRESPONDENCE. 
Are the St. John Pl.\nt Beh.s C.\ri30N1ferous ? The writer has 
been urged to take notice of the opinion of Dr. David White, of the 
United States Geological Survey, expressed as to the age of the St. 
John plant beds, or "fern ledges," as they were designated by the late 
professor C. F. Hartt. 
As long as Mr. White's statement of the age of these beds was ex- 
pressed merely as an opinion based on the composition of the flora 
which these beds contain (which flora he regarded as that of the Potts- 
ville conglomerate of Penn.sylvania. or in English parlance the Mil' 
stone grit*), it did not seem to call urgently for reply. But since ho 
has lately written a communication to the Natural History Society of 
* U. S. Geol. Surv. 20th Ann. Rep. Part ii, General Geology, &c., page 917. 
