1895. ] NEW YORK ACADEMY OF SCIENCES. 207 
In the concentrates a few grains are found of a mineral with 
ultramarine-blue color,and pleochroism ultramarine to colorless. 
This is thought to be probably a soda-hornblende, allied to 
glaucophane. Its refraction and polarization indices are about 
those of hornblende and it is (7) biaxial; but its properties 
could not be further determined. ‘ 
The peripheral phases of the soda-granite are not thoroughly 
known. The complete gradation from it into the felsite-breccia 
described by Dr. Bailey as occurring at Titus’ Mill, the writer 
has not succeeded in finding. At other points the granite was 
seen to be fine-grained and to have lost its characteristic bright 
redcolor. It was not atall gneissic, however, nor was it strongly 
porphyritic, and of further transition between it and the felsites 
ho trace was seen. 
Under the microscope (PL. XVI, fig. 2) this fine-grained facies 
shows a more or less panidiomorphic structure of feldspar crys- 
tals which exhibit a decided tendency towards the rod-like form. 
One or two large crystals appear to be porphyritic in the rest of 
the mass. The feldspar is largely plagioclase, the rest orthociase, 
no anorthoclase being certainly recognizable in the sections. 
Augite? appears in minute grains scattered all through the 
mass; they are too small to show well the characteristic optical 
properties, and have little or no crystal outline. 
An analysis was made of the soda-granite from above Titus’ 
. Mill, spec. 661. This was a fairly average specimen, moder- 
ately granophyric, with an unusually large amount of dark sili- 
cates present. The following results were obtained (column I.): 
ANALYSES OF SODA-GRANITES. 
I. Titus’ Mill, Upham, N. B. 
II. Kekequabic Lake, Minn. U.S. Grant. 
III. Pigeon Point, Minn. W.S. Bayley. 
die ik: Ill 
a b 
SiO, 64.86 64.79 66.84 72.42 
TiO, 0.70 OG Sin Bee ae, oon 0.40 
Al,O,; 15.02 18.22 13.04 
Fe,0, 5.53 5.60 Pied 0.68 
FeO 1.01 0.86 0.20 2.47 
MnO 0.18 O40P Posh Os 0.09 
CaO 2.61 2.63 -3.31 0.66 
MgO 1.42 151 0.81 0.58 
Na,O 3.92 3.93 5.14 3.44 
K,O 2.31 2.35 2.80 4.97 
co, SST 2 ay ly ne? mom ese 2 meee gag = 28 LS 
Ont ae etek fs ae are tr 0.20 
Loss on ign. 1.73 1.78 0.46 1-21 
99.89 100.05 100.37 
