84 THE AMERICAN NATURALIST.  [VoL. XXXIII, 
elers as well as to persons directly interested in the development of 
the countries of which they treat. 
The Botanical Gazette for October contains a sketch, by Mr. 
Norton, of the life of the late Joseph F. Joor, a botanist of Texas 
and Louisiana. 
PETROGRAPHY. 
The Lavas of Two Volcanoes in the Eifel. 
small volcanoes Hochsimmer and Bellerberg, near Mayen, in the 
Eifel, were thought to be similar in composition by the earlier geol- 
ogists. Schottler,t however, reports the Hochsimmer lava to be a 
porphyritic leucitite with phenocrysts of augite, biotite, olivine, and 
hauyne in a groundmass composed of leucite, augite; and glass. The 
Bellerberg lavas are augite-andesites, with phenocrysts of augite and 
biotite in a groundmass composed of augite, plagioclase, a little leu- 
cite, and glass. Olivine, hauyne, and quartz are also present in some 
specimens as porphyritic crystals. The rock approaches in char- 
acter the tephrites. Large numbers of inclusions are imbedded in 
the lavas. Some of them are unquestionably endogenous, while 
others are certainly exogenous. A few consisting of single min- 
erals exhibit no evidence as to their origin. All have been deeply 
corroded by the action of the enclosing magma. ‘The isolated min- 
erals represented among the foreign inclusions are: hauyne, zircon, 
corundum, garnet, olivine, feldspar, and quartz. The rock inclu- 
sions are fragments of graywackes, slates, quartz-feldspar-aggregates, 
cordierite and sillimanite-bearing schists, hornblende-schists and bio- 
tite-schists, augite-feldspar-aggregates, limestone, and sanidine-aggre- 
gates. The limestone inclusions often contain cavities, and in these 
crystals of chalcomorphite, ettringite, and quartz have been deposited. 
The action of the magma on the limestone is seen in the formation of 
feldspars, augite, and glass in the rock surrounding the inclusion, 
and in the production of wollastonite, quartz, and nepheline in the 
inclusion itself. 
A Sedimentary Granite. — Professor Winchell? points out the 
fact that the oldest rocks in Minnesota are the archean greenstones. 
The granites which intrude these are believed to be fused sediments. 
1 Neues Jahrb. f. Min. etc., Beil. Bd. xi, p. 554. 
nAn EEE vol. EE p. 299. 
