1889.] Mineralogy and Petrography. 1091 
the surface of the ground. Under these changed conditions the quartz 
became plastic, and was about to remelt when soHdification resulted- 
Mr. Worth 8 uses the term Elvan to designate rocks that have been 
found by the cooling of a magma with the composition of granite under 
conditions intermediate between those that yielded plutonic rocks and 
those that gave rise to surface rocks. He calls attention to the many 
different structures possessed by these elvans even in the same dyke. 
Miss Raisin ^ declares that the greenstone-schists near Redlap, S. 
Devon, Eng., are crushed diabases, in which secondary changes have 
taken place. The article denies the correctness of certain conclusions 
with regard to the character of these rocks, as drawn by Mr. Somer- 
vail, 10 who thinks them chlorite schists. Mr. Goodchild " does 
not believe that the paste of limestones is the result of the breaking 
down of shells. He ascribes it to chemical precipitation, due to the 
reaction of decomposing organic matter upon the sulphate of calcium 
so abundant in sea water. Berwerth^^ declares that the rock from 
Pizzo Lunghino described by himself and von Tellenberg as jade, is 
a'granular aggregate of vesuvianite and sahlite, of which the latter is 
the younger. 
Mineralogical \i\^^^.— Crystallographic. — Traube^^ has discovered 
seventeen new forms in cinnabar from the barite veins cutting horn- 
stones near Mt. Avala in Servia. Four of these are trigonal pyramids 
rV K-2, \ R2, 7 R2 and | R2, and the others are rhombohedra— yV R. 
tV R, I R, I R tV R, a R, I R, H R, y R, f R, f R, I R. and 16 
R- The plane 6P2 which has been reported as occurring in the min- 
eral, is found by more accurate measurements to be 4P2, so that up to 
this time 74 forms have been detected in cinnabar. The calomel i\i2X 
covers quartz and cinnabar crystals in this vein was also carefully ex- 
amined by Traube. On tantalite from Pisek, Bohemia, Urba" finds 
the new planes 6P^, 3P^, fP|, P|, P-g. Good crystals of the rare 
mineral parisite (Medici-Spada's musite) from New Granada afford 
an opportunity for more complete measurements of this mineral than 
have heretofore been possible. Its habit is short hexagonal or columnar, 
with an axial ratio a: r=ri: 3. 36 46. Its specific gravity is A-i,^\- 1" 
8 Quart. Jour. Geol. Soc, Aug., 1889, p. 398- 
Geological Magazine, Feb., 1890, | 
"^■\nn. K.K. Naturhis. Hofmus. V 
" Zeitsf. Kryst., XV., p. 563. 
" Zeits.f. Kryst., XV., p. 194. 
