184 
The American Geologist, 
March, 1896 
case there has been no dynamic action. The only agencies at work 
since the close of eruptive activity have been those of decomposition 
and erosion. 
If we grant that it is conceivable that palseorhyolites and neorhyo- 
iltes may acquire the habit of eorhyolites, due to the same processes of 
devitrification, and associated changes, is it not well to have a common 
term for all rhyolites of that habit, leaving their age to be indicated by 
an additional prefix, or by an adjective, as in the case of the deep- 
seated rocks? e. b. 
New and Interesting Species of Palaeozoic Fossils. By S. A. Miller 
and Wm. F. E. Gurley. (Bulletin No. 7, Illinois State Museum of Nat¬ 
ural History; 89 pp., 5 pis.; Springfield, Ill., December 5, 1895.) The 
present Bulletin introduces among Paleozoic Crinoidea alone, no less 
than four new generic and 56 new specific names, which are applied to 
specimens, not in the State Museum, but in private collections, espe¬ 
cially those of the authors. When we see the names of these two 
gentlemen on a title page we know what to expect. Detailed criticism 
becomes a work of superogation. The character of the work and the 
competence of these “distinguished and laborious collectors,” as they 
presumably would wish to be described, may, however, be gathered 
from an examination of some statements on the first page that opened 
to my hand. 
On pp. 80, 81 the writers describe “Pisocrinus milligani n. sp.” 
found by Mrs. Milligan, in the Niagara group of Decatur Co., Tenn. 
This species is said to resemble Pisocrinus gorbyi , which, however, is 
longer in proportion to the diameter. The cup “expands in the radial 
regions, giving to the upper part a pentalobate aspect.” A specimen 
that “does not show the sutures in the calyx” is figured, and it is 
stated that “ Figs. 21, 22 and 23, on Plate VI of the 17th Report of the 
Geological Survey of Indiana belong to this species.” 
Permit me now to quote a paragraph from “ The Crinoidea of Got¬ 
land. Part I.” ( Kgl . Svenska Vet.-Akad. Handlingar. Bd. XXV, 
No. 2; 1893.) On p. 27 it is written, “ The nomen nudum et barbari- 
cum ‘ Pisocrinus pentalobus^ W. and Sp.”, which occurs in a note by 
Mr. C. S. Beachler as indicating a species found in Niagara beds at St. 
Paul, Decatur Co., probably refers to P. Gorbyi. (Amer. Geol., March 
1891, p. 179. The more correct quinquelobus would admirably suit the 
new Tennessee form.) It is, however, a little uncertain whether P. 
gorbyi does not include two species. I have, for some years, been 
acquainted with a species from the Niagara group of W. Tennessee, of 
which the following is a diagnosis:—Dorsal cup low ; pentagonal as 
seen from ventral surface, the angles of the pentagon being radial in 
position: the radial facets are very narrow, the radial processes corres¬ 
pondingly broad, forming the concave sides of the pentagon : basals 
hidden in the concavity for the stem. Now, this seems to agree with 
specimens collected by Prof. Gorby in W. Tennessee and figured by 
* Whitman Cross: Geology of the Rosita hills* Custer Co., Colo. Proc. Col. Sci. 
Soc., 1890, p. 279. 
