| PUBLICATIONS. ms 501 
Order of crystallization. 
Flow structure. 
Implication structures (micro, and crypto-pegmatite). 
Spherulitic structure. 
Spheroidal (kugel) structure. 
7. Perlitic partings. 
The original appearance of these rocks cannot be described, for 
they have been completely altered by dynamo metamorphism and its 
attendant changes, among which devitrification has been most active. 
Throughout the paper the prefix co, as in eorhyolite, is used to 
show the relation of the old volcanic to the newer type with which it 
is closely connected. ‘This brings in the troublesome age question in 
classification. At present there is a reaction against the use of age 
terms in petrography, and it would be better to employ the prefix ao, 
as suggested at nearly the same time by Miss Bascom,” and thus avoid 
the old discussions and objections. Dr. Nordenskjéld refers to this 
prefix in a note at the end of his paper, and signifies his willingness 
to adopt the apo joe if it is regarded by petrographers as a better 
one. G. PERRY GRIMSLEY. 
PE eae A 
[Several reviews intended for this number are deferred to give place to standard 
articles. | 
RECENT PUBLICATIONS: 
—AGASSIZ, ALEXANDER, A Reconnoissance of the Bahamas and of the Ele- 
vated Reefs of Cuba in the Steam Yacht ‘‘ Wild Duck,” January to 
April, 1893, 203 pp., 47 plates.—No. 1, Vol. XXVI. Bulletin of the 
Museum of Comparative Zodlogy at ce College. 
—BAIN, H. Foster, Preglacial Elevation of lowa, 4 pp. _ Pree, Iowa 
Acad. Sci., Vol. II., 1895. Interloessial Till near Sioux City, Iowa, 4 
pp.—Proc. Iowa Acad. Sci., Vol. II., 1895. 
—BARROIS, CHAS., Le Bassin du Ménez-Belair, 350 pp. and g charts.— 
Légende de la Feuillé de Plouguerneau et Ouessant, 99 pp.; Légende 
de la Feuille de Rennés, 17 pp. 
—Bav_ErR, Louts A., Beitrage zur Kenntniss des Wessens der. Sadcular- 
Variation des Erdmagnetismus, 54 pp., 2 charts. 
—BELL, ROBERT, Honeycombed Limestones in Lake Huron, 7 pp., 3 
plates.—Bull. Geol. Soc. Am., Vol. VI., March, 1895. 
—BRIGHAM, A. P., Drift Bowlders between the Mohawk and Susquehanna 
Rivers, 15 pp.—The Am, Jour. of Sci., Vol. XLIX., March, 1895. 
TJOURNAL OF GEOLOGY, Vol. L., p. 813, 1893. 
