Authors' Catalogue. 257 
of diabase (one analysis), and dikes of labradorite porphyry or por- 
phyritic diabase. The work closes with a brief account of the ex- 
tensive rocks, including the rhyolyte and keratophyre of Marblehcad 
Neck, and with an analysis of each. w. o. c. 
A contribution to the Geology of the Pre-Cainbrian Igneous Rocks 
of the Fox River Valley, iVisconsin. By Samuel Weidman. (Wis. 
Geol. and Nat. Hist. Survey, Bull. No. 3, Science Series' No. 2, 1-63.) 
The areas of igneous rocks described in this paper are a part of the 
cordon of hills and ridges of pre-Cambrian rocks that lie outside the 
more continuous crystalline core of central and northern Wisconsin. 
These outlying hills were islands in the early Paleozoic seas, and around 
them are deposited the later horizontal formations of sandstone and 
limestone. Among the pre-Cambrian outliers are to be found rocks 
of both sedimentary and igneous origin; but those of the Fox River 
district are wholly igneous, of both plutonic and volcanic nature. 
Three types are described in great detail, viz., the Utley nietarhyolyte, 
.Berlin rhyolyte-gneiss, and Waushara granite. They are regarded as 
of Keweenawan age, and the close agreement of the bulk analyses 
shows that they are essentially consanguineous and belong with the 
Baraboo rhyolyte to a petrographic province of considerable extent. 
The acid character of these rocks limits the mineral composition 
chiefly to quartz and feldspar. An analysis of the feldspar phenocrysts 
of the Utley metarhyolyte shows that they are a soda-lime feldspar 
with a considerable amount of potash; and in harmony with this 
composition, the microscope reveals in most cases a microperthitic 
structure. This is discussed at some length and shown to be partly 
original and partly secondary; and the latter is believed to be due in 
part to an enlargement or outgrowth of the original plagioclase 
phenocrysts, and in part to intergrowths or regeneration of older 
plagioclase, the latter process being regarded as allied to paramor- 
phisni and not unlike the process of schillerization as described by Judd. 
w. o. c. 
MONTHLY AUTHORS' CATALOGUE 
OF American Geological Literature, 
Arranged Alphabetically.* 
Bailey, E. H. S- (G. P. Grimsley and) 
Special report on Gypsum and Ciypsum cement plasters. (Kans. 
Univ. Geol. Sur., vol. 5, pp. 183; plates and maps, Topeka, 1899.) 
Beecher, Chas. E. 
Othniel Chark-s Marsh. (American Geologist, vol. 24, Sept. 1899, pp. 
135-157, portraits.) 
*Tliis list includes titles of articles received up to the 20th of the preceding 
month, including general geology, ph.vsiography, paleontology, petrology and 
mineralogy. 
