52 The American Naturalist. [January, 
WILDER, H. H.—Lungless Salamanders. Extr. Anat. Anz. XII Bd., 1896. 
From the author. 
WOLTERSTORFF, W. AND JOH. BorHM.—Ueber fossile Frösche aus den altpleis- 
tociinen Kalktuff von Weimar und Taubach. Adbruck a. d. Zeitschr. d. Deutsch. 
Geolog. Gesell. Jahrg. 1896. From the author. 
General Notes, 
PETROGRAPHY.' 
The Basic Rocks of Devonshire.—The diabases of southern — 
Devonshire, England, have been carefully investigated by Busz.’ The — 
diabases occur in floors often between Devonian slates and schists. The — 
plagioclase of a specimen from Anstie’s Cove, near Torquay, is partially . 
changed to prehnite. All specimens contain brown hornblende, which — 
is regarded as original. At Babbacombe the diabase is full of porphy- 
ritic crystals of labradorite. The groundmass in which these lie is- 
composed of a second generation of plagioclase in a serpentine-like sec 
ondary matrix, which has been derived from the augite and other com- 
ponents of the original rock. Both porphyritic and groundmass pla | 
gioclases are deformed as the result of pressure. At Highweek blocks — 
of a pale pikrite were found. Their material is identical in appearance — 
with the rock of Nassau. It consists of olivine, augite, feldspar, bie 
tite, enstatite, apatite and magnetite. The rock is very much alte 
Its composition, as shown by analysis, is: 
SiO, Al,0, Fe,0, FeO CaO MgO Na,O K,O H,O TiO, P,O, FeS, Total — 
40.12 7.76 7.35 8.66 6.53 23.69 1.20 58 4.03 .37 .18 2010 
It contains also traces of Cl, CO, and Cu. 
Along the banks of the Avon, at South Brent, blocks of Kersantite 
are met with. The rock possesses no noteworthy features, except that : 
in it are crystals of orthoclase surrounded by zones of newly formed 
plagioclase. 
The Magmatic Alteration of Hornblende and Biotite.— 
Hornblende and biotite in many igneous rocks are surrounded by i 2 
of augite and magnetite that have resulted from their alteration. 
process by which this zone or rim has been formed is generally cal 
1 Edited by Dr. W. S. Bayley, Colby University, Waterville, Me. 
? Neues Jahrb. f. Min., ete., 1896, I, p. 57. 
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