Review of Recnt Geological Literature. 273 
greater in the interior of the basin, — the Coal Measures were deposited. 
A rapid, continuous, or a frequently recurring subsidence would pre- 
vent the accumulation of coal, or would limit its formation to narrow 
marginal areas. A few simple diagrams make the process of deposition 
and the relations between the dififerent strata easily understood. A 
study of the hypothesis presented shows how a moderate amount of 
erosion will suffice to produce the present limitations of the upper 
strata; how coal beds are more abundant over the marginal area; how 
the interval between any two strata may be very different at dififerent 
points; that a columnar section constructed from outcrop measurements 
of successively exposed strata from margin to topmost layer will not 
represent the succession of strata in the interior; that a coal bed may, 
at one point, immediately overlie strata which are widely separated at 
another point; that the strata at the margin are not necessarily the 
lowest; that sandstone, shale or limestone may be prevalent according 
as the beds were marginal, shallow water or marine portions of the de- 
posit. ■ 
The Missouri survey is to be congratulated upon the production of 
such a neat and handy volume, also upon its subject matter and ar- 
rangement, as well as its typography. It is certainly one of the best 
appearing reports yet issued by a state survey. 
'Die Journal of Oeology, is a new publication, "A Semi-quarterly Mag- 
azine of Geology and related Sciences," whose editors are T. C. Cham- 
berlln, R. D. Salisbury, J. P. Iddings, R. A. F. Penrose, C. R. VanHise, 
C. D. Walcott and W. 11. Holmes, with a number of associate editors, 
some of them being European. It is issued under the auspices and 
guarantee of the Chicago University. Its purpose is to discuss some of 
the broad and deep problems of the science of geology — systematic, phil- 
osophical, fundamental geology— in its inter-state and international 
relations. The first number contains: 
On the pre-Cambrian rocks of the British isles, Arch. Geikie ; Are 
there traces of man in the Trenton gravels? W. H. Holmes ; Geology as 
a part of a college curriculum, H. S. Williams ; The nature of the engla- 
cial drift of the Mississippi basin, T. C. Chamberlin : with editorials and 
reviews. 
Phases in the metarnorphistn of tlie sch'istsof southern Berkshire, by 
William H. Hobbs. Bull. G, S. A., Vol. IV, pp. 167-178, Feb. 27, 1893. 
Certain so-called porphyrltic minerals occurring in the crystalline schists 
of southwestern Berkshire county, Massachusetts, and northwestern 
Litchfield county, Connecticut, are described in this paper. These min- 
erals are foldspar(an acid plagioclase), garnet, staurolite, tourmaline, bio- 
tite and ottrcllte. Secondary enlargements of feldspar, garnet and tour- 
maline are discussed and figured. Those of feldspar are the most inter- 
esting; here the enlargements aregenerally of a more basic character than 
the cores, as is shown by the extinction angle. In cases of feldspar 
twins the enlargement is sometimes twinned in the same manner as the 
original grain, and again the enlargement is untwinned. Granophyric 
