1892. ] NEW YORK ACADEMY OF SCIENCES, 65 
and referred to this cause rather than to pressure. A deep reddish- 
brown biotite is also occasionally present, but is far more abundant 
toward the south of this upper third of the dike. Its colors are 
those of the biotite commonly seen in nepheline rocks, but it has a 
well-marked divergence of the optic axes. It affords an excellent 
percussion (schlag) figure, and the plane of the optic axis is parallel 
to the principal ray (010), proving it a mica of the second order, 
as is to be expected. It occurs in irregular shreds, and is older 
than the aegirine. The most micaceous normal syenite is a short 
distance south of Thomas Conway’s house. Titanite is usually 
present, and from decomposed syenite small crystals (0.5 mm.) can 
be picked out which show good faces. They are honey-yellow 
in color. Professor Rosenbusch, to whom I have sent a suite of 
specimens and with whom I have had some correspondence, re- 
marks the passage of the titanite into bordering rutile nets. He 
also has noted the occasional presence of fluorite, ‘which has escaped 
my notice. Small amounts of magnetite are wenerally seen, and 
pyrite is common. 
A partial analysis (I.) of number 34, which was collected as nearly 
as I could determine from the point visited by Professor Emerson, 
was kindly made by Mr. F. W. Love, of Cornell University. The 
complete results were not obtained in time to insert, but will be dis- 
tributed in the reprints. Column II is the ditroite of Hungary 
(Fellner, Verh. d. k. k. Geol. Reichsanstalt, 1867, 286, quoted by 
Rosenbusch, Tsch. Mitth., xi, 144, Taf. 1). Column III is the 
' elaeolite-syenite of Brazil (Machado, Tsch. Mitth., ix, 334). Col- 
umn IV. is the elaeolite-syenite of Arkansas (J. F. Williams, 
Igneous Rocks of Ark., p. 81). Column V is the Norwegian 
elaeolite-syenite (Brogger, Syenitpegmatitginge, p. 33). 
ie Il. TU Vis; Vi 
Loss . A 3 9.512 1.6 3.60 1.88 0.22 
SOE ss . 50.36 56.3 52.75 59.70 ° 51.90 
INNA OR ton 24.1 22.55 18.85 22.54 
HesOe. . « 6.94 2.0 3.65 4.85 4.03 
ReO'r. £ 3 — — — —_— 3.15 
CaO 345 0.7 185 1.34 Seidl 
MgO — 0.1 0.15 0.68 ao 7 
K,O E — 6.8 7.05 Deon 4.72 
Na,O — 9.3 8.10 6.29 8.18 
100.9 99.70 99.56 99.82 
It thus appears that the Beemerville rock is rather basic in its 
chemical composition. Several pounds of the rock were crushed 
fine and panned for small minerals of high specifie gravity, but only 
aegirine, titanite, magnetite, and a little apatite resulted. Emerson 
found a variety that was nearly pure elaeolife, and much the same 
has been met by me along the contact just above Thomas Conw ay’s 
house. The rock is very finely crystalline and contains wavy lines 
of aegirine and biotite, due to flow structure. The biotite, at times, 
