262 The American Geologist. October, 1895 
of the Pennsylvania Survey. All are in a N. W.-S. E. direction and are 
viewed from the south. H. D. Rogers held it to be a general law for 
eastern Pennsylvania that northwesterly dips are steeper than the 
southeasterly ones. Mr. Lyman concludes, from the study of these sec- 
tions, that "steep northerly dips in the Pennsylvania anthracite region 
are much less prevalent than was formerly supposed; that nearly half 
of the basins and saddles are about symmetrical; * * * that the sub- 
ordinate folds throughout the region are confined to subordinate groups 
of beds of inferior firmness, and are not parallel to the main folds, but 
probably at uniform profile-distances from the main axes, so as to de- 
scend the flank of a sinking anticlinal. Further, that the faults are al- 
most invariably longitudinal or reversed faults, occasioned by the over- 
straining of subordinate folds." j. M. c, 
Directions for Collecting and Preparing Fossils. By Charles 
ScHucHERT. (Bull. U. S. Nat. Mus., no. 39, part K, pp. 1-31, 1895.) The 
paleobiologist of to-day is making such exactions of the collector and 
has raised to such a fine art the preparation of fossils that concise sug- 
gestions such as Mr. Schuchert has here brought together from his own 
and others' experience will be found of general usefulness. The best 
collector is the one who collects as much by faith as by sight, and the 
most skillful preparateur he who adapts his methods to the nature of 
his subject. j. m. c. 
On a Neui Trilobite from Arkansas Loirer Coal Measures. By A. W. 
VoGDEs. (Proc. Cahfornia Acad. Sci., ser. 2. vol. iv, p. 589, 1895.) 
Describes Grifflthides ornata> as a new species, from Conway county, 
Ark. Its similarity to G. scitula, Meek & Worthen and G. cliftonensis, 
Shumard, is pointed out and the suggestion made that all may prove 
referable to Shumard 's species. j. m. c. 
A Supplement to the Bibliography of the Palaeozoic Crustacea. By 
A. W. VoGDEs. (Proc. California Acad, of Sci., ser. 2, vol. v, pp. 55- 
76, 1895.) Gives 141 titles of papers published since 1893 or omitted 
from the author's larger work of that date. It is an important addition 
to that very useful compilation. j. m. c. 
Tables for the Deterinination of Common Minerals, chiefly by their 
physical properties, vrith confirmatory chemical tests. By W. O. Crosby, 
Ass't Prof, of structural and economic geology in the Massachusetts 
Institute of Technology. (106 pp.; third edition, rewritten and enlarged; 
Boston, 1895, published by the author. Price, $1.25.) In these tables 
the author has endeavored to do away with, as far as is possible, elabo- 
rate chemical tests in the determination of minerals. The more obvious 
physical properties are used as the chief means of determination, the 
general classification being based entirely on physical characters. In 
this classification the minerals are divided into two great classes, metal- 
lic and non metallic, according to their luster. Under each of these 
classes are five subclasses, distinguished according to the color in the 
metallic and according to the color of the streak in the non-metallic. 
