274 The American Naturalist. [March 
lines, spherulites, lithophysae and amygdaloidal cavities. Quartz and 
an alkaline feldspar are the prevailing phenocrysts, while the ground- 
mass is a quartz-feldspar mosaic. The basalts are much altered, but 
their structure is clearly that of an eruptive. A detailed account of 
the rocks is promised later. 
The Nepheline and Leucite Rocks of Brazil.—A more 
careful study of a few of the Brazilian nepheline and leucite rocks 
undertaken by Hussak* has resulted in the discovery of leucite in some 
of the phonolites, and in the detection of leucite-tephrites containing 
pseudo-crystals. The leucitophyres consist of phenocrysts of sanidine, 
augite, nepheline and pseudo-leucites in a groundmass of small zeoli- 
tized leucites, augite, magnetite and nepheline. The leucite-tephrites 
are all characterized by the possession of the pseudo-leucites. In many 
eases these are nothing but spherical masses of the rock material sur- 
rounded by biotite plates. In other cases the biotite surrounds anal- 
cite or mixtures of analcite and calcite. The structure of several of 
these rocks is the diabasic. With these the author would place a rock 
described by Eigel’ from the Cape Verde Islands, and the augite-por- 
phyrite described by Kemp" from Deckertown, N. J.,in both of which 
traces of leucite are thought to have been discovered. Hussak has 
also found a leucitite dyke in phonolite near Pocos de Caldas, and a 
leucitite tufa composed of fragments of basalt, isolated crystals of 
leucite changed to analcite, pieces of augite and crystals of magnetite. 
The author concludes his paper with remarks on ‘ pseudo-erystals’ 
combating the view of Derby that they are true leucite erystals filled 
with inclusions of the rock’s groundmass. 
The last named writer" has examined the Peak of Tingua with some 
care, finding eleolite-syenite, phonolite and dykes of basic rocks. The 
syenite and phonolite are thought to be phases of the same magma, as 
they apparently grade into one another. The phonolitic phase occurs 
both in dykes and in flows associated with phonolite tufas. The origin 
of the pseudo-crystals is discussed briefly. 
| Petrographical News.—Brauns” has discovered hauyne in the 
pumice sandstone near Marburg, a mineral hitherto unobserved in the 
ŝNeues, Jahrb. f. Min., etc., 1892, II, p. 141. 
PAMERICAN Naturatst, Feb., 1892, p. 165. 
VSee above under ‘The New Jersey Eleolite-Syenite.’ 
"Quart. Jour. Geol. Soc., May, 1891, p. 251. 
*Zeits. d. deutsch. geol. Gesell., xliv, 1892, p 149." 
