Review of Recent Geological Literature. ' 53 
sibilities of the method are farther illustrated by grouping the dia- 
grams in natural series, which show progressive changes in form; and 
also by introducing a composite of each series. The numerous an- 
alyses upon which the diagrams are based are quoted in tabular form. 
w. 0. c. 
The Nomenclature of Feldspathic Granolites. By H. W. Turneh. 
(Jour. Geol., 8, 105-111.) 
Accepting the principle that the classification of granular rocks, if 
not of lavas, should be based on mineral composition, the author notes 
that this is equivalent to a classification based on molecular composi- 
tion in so far as the minerals are composed each of one kind of mole- 
cules. But plagioclase is an exception, since it is composed of two 
kinds of molecules in ever varying proportions. The author proposes 
that the molecular classification be applied throughout; and hence in 
calculating the composition of the feldspathic rocks the plagioclase 
should be resolved into the constituent albite and anorthite molecules, 
and the name plagioclase should not be used. This is shown to be 
particularly necessary with the monzonytes and diorytes, which con- 
tain both orthoclase and plagioclase, since the plagioclase may vary 
from a basic labradorite to an acid oligoclase, thus giving rocks which 
could not properly be designated by the same name. It is suggested, 
therefore, that if we subdivide the feldspathic rocks on the basis of the 
ratio of the alkali-feldspar molecules (Or -(- Ab)g to the lime feldspar 
molecules (An) the true mineral and chemical relations of the rocks 
will be brought out and a better classification result. A graphic illus- 
tration is given in tables showing percentages of the alkalies and lime 
and the ratios of Or -f-Ab to An for the principal feldspathic types. The 
author further suggests the use of mineralogical terms in naming 
granolytes of simple composition, as orthosyte for a rock composed 
chiefly of orthoclase, albityte for one composed chiefly of albite etc., 
the names of other essential constituents to be used in substantive 
forms, as quartz-orthosyte or granite, and of accessory constituents in 
adjective form, as quartziferous syenyte etc. w. 0. c. 
Some Contact Phenomena of the Palisade Diabase. By John Duer 
Irving. (School of Mines Quarterly, 20, 213-223.) 
This paper, which, after noting the gradation in texture, density 
and mineral composition between the central and peripheral portions 
of this great trap sheet, is based chiefly upon the exposures of the upper 
and lower contacts afforded by the new tunnel of the New York Sus- 
quehanna and Western railroad, confirms in the main the work of An- 
drae and Osann, who in 1892 studied the lower contact only, as ex- 
posed by the West Shore railroad. The earlier work recognized four 
metamorphosis phases of the Triassic shale and sandstone, as follows : 
(i) normal hornfels, (2) the same rich in tourmaline, (3) altered ark- 
ose containing green hornblende, (4) lime-silicate hornfels. To these 
Irving adds five others, three from the lower contact: (i) normal 
hornfels rich in spinel, (2) lime-silicate hornfels containing brown 
