Correspondence. 315 
tory of Mono valley, Cal., by I. C. Russell; The Geology of the 
Lassen Peak District, by J. S. Diller ; The Fossil Butterflies of Floris- 
sant by S. H. Scudder. Part II contains an exhaustive monograph 
of 157 pages on The Trenton Limestone as a Source of Petroleum and 
Natural Gas by Edward ORTON;an important addition to palseobotany, 
The Geographical Distribution of Fossil Plants (300 pages) by Lester 
F. Ward ; A Summary of the Geology of the Quicksilver Deposits of 
the Pacific slope, by George F. Becker, and The Geology of the Island 
of Mt. Desert, Me., by N. S. Shaler. 
The Potomac or Younger Mesozoic Flora, by W. M. Fontaine. Mon- 
ograph No. XV, U. S. Geological Survey. Part i, text o.37 pp. Part ii, 
180 pi. The greater number of species described in this monograph 
are new and important. Of the cryptogams there are three new gen- 
era and 137 new species. Of the phanerogams two new genera and 17 
new species, of gymnosperms seven genera and 89 species of conifers. 
Among the angiosperms 19 new genera and 72 new species. 
CORRESPONDENCE. 
The Genus Terebellum in American Tertiaries. — While looking 
over some material in the collection of the United States National 
Museum from the Eocene formation of Texas,* several beautiful and 
well preserved casts of a small Terebellum were observed. This the 
writer believes to be the first time the genus has been noted in theTertiary 
formation of this country. The species mentioned under this genus by 
Tuomey and Holmes from the Pliocene of South Carolina^ belong 
properly to Turritella as the term is ordinarily used. The Texas forms 
are somewhat elongate, and, when studied more carefully, will perhaps 
be found to belong to the section, Terebellopsis , Leymerie. 
U. S. Geological Survey, April 3, 1890. Gilbert D. Harris. 
The American Neocomian and the Gryph.ea Pitcheri — "x\. prelim- 
inary annotated check list of the Cretaceous invertebrate fossils of 
Texas," by Robert T. Hill, Geological survey of Texas, Bulletin No. 
4, Austin, 1889, is too important a paper not to point out a few incor- 
rect statements, which, very likely, have escaped professor Hill's at- 
tention in the haste of preparation, such a work being alw'ays attended 
by great difficulties as to exact references and the right of priority. 
We read at p. vii : "It is now known that the series of rocks -which 
a few years ago were considered as the whole Cretaceous group of the 
United States, east of the Rocky mountains, on the section pul)lished 
'Station No. 2056, Eocene, Mt. Enterprise, in the southeastern part 
of Rush county, Texas, L. C. Johnson, U. S. Geol. Sur., Collection. 
"'■Terebellum striatum T. & H., 2'. esaltatum Con., T. etiivanensis T. it 
H., T. burdenii T. & H. "Fossils of South Carolina, Pliocene and 
Post- Pliocene," Tuomey and Holmes, 1855-60, p. 120-122, pi. 26, figs. 
7-11. 
