Review of Recent (ieoloijical Llterafure. 119 
tion of the work which will appeal most directly to the people actually 
engaged in working in the diggings. 
\ considerable part of the report is devoted to a description of the 
general topographic and geologic features of the state. So much detail 
may seem unnecessary; Mr. Winslow states that "The writer has en- 
deavored to embody, and thus to place on record, all the notes of im- 
portance relating to the geology of the southern part of the state, which 
he accumulated during his occupancy of the position of state geologist 
and which the recent severance might prevent the jiublication of." Mr. 
Robertson has already pviblished in the American Geologist (vol. xv, 
pp. 235-248, April, 1895,) a comprehensive abstract of this report on the 
lead and zinc deposits of Missouri. 
"A Study of the Cherts of Missouri," by Dk. E. O. Hovey, is em- 
braced in the appendix. The two volumes in size and general appear- 
ance are similar to the other excellent reports of the Missouri Survey. 
u. s. G. 
0)1 Some Dykes Containing Huronite. By Alfred E. Barlow. 
(Ottawa Naturalist, vol. ix, no. 2, pp. 25-47, 1835.) In this paper, read 
before the Geological Society of America at the Baltimore meeting, 
there is a full description of the known occurrences of this mineral. 
Huronite was described by Thompson in 1833 as a mineral species from 
material obtained from a diabase boulder on Drummond island, lake 
Huron. The exact relationship of this mineral has been open to some 
doubt. Dana originally placed it under prehnite and later mentions it 
as a supposed altered form of iolite. T. Sterry Hunt considered it "an 
impure anorthite-like feldspar related to bytownite," and on the same au- 
thority Dana speaks of it as "an altered mineral near fahkmite." In 
1885 Dr. B. J. Harrington examined the mineral, using material from 
Pogamasing, and upon this authority it is in Dana's last edition placed 
under anorthite. Michel Levy and Lacroix considered it a decomposi- 
tion product of iolite or cordierite. 
For some time after the original description of the mineral it was not 
known from material fovmd in situ. Knowledge on the subject has been 
accumulating until in the present paper it is described from eleven lo- 
calities. The doubt as to the correct position of the mineral arose from 
the fact that its true nature could not be discovered by analysis. Mr. 
Barlow studied the material with the microscope and discovered "that 
in every case the so-called huronite is really a plagioclase near the basic 
end of the series which has undergone more oi- less complete saussuriti- 
zation." 
In the present jjaper the results of this detailed petrographic study of 
material from the different localities are given and the different stages 
in the alteration are traced. h. f. ij. 
On La irsonite, a Neiii Rock-forming Mineral from the Tibitron Pe- 
ninsula. Marin Co., Cal. By F. Leslie Ransome. (Bull. Dept. Cieol. 
Univ. Cal., vol. 1, no. 10, pp^ .301.312, pi. 17, May, 1895.) This is a clear 
and colorless or gray -blue mineral which occuis as an important rock- 
