Review of ^Recent Geological Literature. 125 
7. Subsequent to the cessation of the glacial floods, the streams 
carved the flood-plains into terraces. 
(i) Fulgurite from Mt. Thielson, Oregon By J. S. Diller. (From the 
American Journal of Science, Oct. 1884.) 
(2) Per idotytc of Elliot county., Kentucky. By J. S. Diller. (Bulletin 
No. 38 of the U. S. geological survey.) 
(3) Notes on the geology of northern California. By J. S. Diller. (Bul- 
letin No. 33 of the U. S. geological survey.) 
(4) The latest volcanic eruption in northern California, and its peculiar lava. 
By J. S. Diller. (From the American Journal of Science, Jan., 1887.) 
In (i) the peculiar product of lightning on a mountain peak of hyper- 
sthene-basalt is analyzed both chemically and microscopically. The ful- 
gurite is formed by the fusion of the groundmass of the rock. A trans- 
verse section through the wall of the glassy tube revealed under the 
microscope three bands of varying effect of fusion. The inner band, the 
most perfect fulgurite, a light coffee-brown glass, was cooled so suddenly 
that it exhibits an entire absence of all crystallites and microlites, a char- 
acter which the author thinks may serve to distinguish it from other 
natural glasses such as hyalomelane and obsidian. In the central belt a 
fluidal banding parallel to the length of the tube is apparent, in which 
are preserved more or less evident remnants of the original crystals of 
the basalt. The third belt consists of the unaltered rock. 
In the description of the Kentucky peridotyte Mr. Diller gives the 
mineral composition and structure, its relations and origin, its chemical 
composition and its age. He concludes that it is closely related to 
dunyte, such as occurs in North Carolina. It contains olivine in well 
defined crystals, pyrope and ilmenite, the former with a fibrous border of 
secondary^ biotite. The olivine is much changed to serpentine. The 
dike occurs in rocks of Carboniferous age, of which it includes frag- 
ments, and from which it has received endomorphic effects in the form 
of a sphaerolitic structure. Mr. Diller's first account of this peridotj-te 
appeared in the Am. Jour. Sci., Aug., 1886. 
In bulletin No. 33 are brought out some important generalizations re- 
specting the Coast and Sierra Nevada ranges in northern California, viz: 
(a) The limestone among the metamorphic rocks of the Coast and Sierra 
Nevada ranges is of Carboniferous age. (b) The northern portion of the 
Sierra Nevada range, like that of the great basin, is composed of tilted 
orographic blocks separated from one another by great faults, (c) The 
greater portion of the range is formed by one of these blocks, with a 
short abrupt slope toward the great basin, and a long gentle slope in the 
opposite direction, (d) The displacements by which the Sierra Nevada 
range was separated from the great basin probably began about the close 
of the Tertiarj', and may be yet in progress, (e) A large portion of the 
auriferous slate series is apparently older than the Carboniferous lime- 
stone, (f) During the Cliico epoch a large part of the region now occu- 
pied by the Coast range was an island, separated by a wide strait from 
