248 . H. P. CUSHING—SYENITE-PORPHYRY DIKES. 
of them taken at 20 degrees centigrade, together with other characters. 
No. | County. | Width. | Strike. Wall rock. | Sp. er. Color. 
Ii © Shits 
28 | Clinton..| 7 S. 75° E..| Anorthosite.| 2.604 | Red. 
25 Sees Wo) == IB aeeseve ga Gneiss ..... 2.605 | Grayish red. 
29 ss 1 10 | N. 85° E.| Anorthosite.| 2.621 | Red. 
107 eS 5+ (?) Gneiss ..... 2.627 | Red. 
31 e it N. 80° E.| Gneiss ..... 2.654 | Dark gray. 
df aa 2 7 | S. 80° E..| Anorthosite.| 2.661 | Dark red. 
21 Seat BIN SOP JD)3) Cnneiss) 25650 2.662 | Red. 
3 | Franklin.| 27 4+) N. 55° E.| Granite.....| 2.663 | Flesh color, spotted 
. with black. ‘ 
27 | Clinton. .| 20 + Wise Gneiss .....| 2.673 | Greenish gray. Red- 
. violet phenocrysts. 
103 oe] @ @ | Si SO? 1B.) GSS 3500: 2.689 | Dark gray. 
He | IAMS scan Gon ets Gneiss .... 2.712 | Dark greenish gray. 
32 | Clinton. .| 10 + S. 80° E..| Gneiss ..... 2.714 | Grayish red. 
Cy 2 28 30 + N. 70° E.} Gneiss .... | 2.716 | Dark gray, reddish 
tinge. 
9 “..| 10 3 | N. 60° E.| Anorthosite.| 2.766 | Black, red spots. ~ 
The average specific gravity of the 14 specimens is 2.669. Numbers 
28 and 107 are somewhat more altered than the rest, so that the results 
from them are probably too low. An inspection of the table shows that 
in general the wider dikes are heavier or more basic than those of slight 
width, though this is not universal and perhaps of no significance. 
CHEMICAL COMPOSITION 
Analyses 
| 
I II III IV Ve VI VII 
Si@ ite teh rae ecg 63.02 68.96 52.53 67.16 65.66 62.28 63.20 
AL Ogoeeeg eek 14.87 15.25 18.31 14.53 20.05 19.17 17.45 
Bes Oe coat a pana, 6.53 3.28 0.34 4.17 | Trace. 3.39 t 3.60 
FeO ee arrears OPA S A ere rere stenacs Traces ber esa i 
MnO, oh Ae eee ay 0.46 0.23 OSES REtGaawe OLS is Soe sal A eee 
CaQ pease ae 1.12 0.76 3.15 1.26 0.67 1.44 1.40 
Mio @ eae 0.95 0.20 1.82 0.41 0.18 | Trace. 0.75 
KOU oe elanee ee 9.62 5.01 6.47 6.10 6.98 5.93 5.88 
Na @) Se ero ane: 5.85 5.45 7.26 5.09 6.56 5.37 6.90 
JEN em RN leg aa ages Met 2 IS OE eaten os | oe Ace ee | 
DRS ean arches en eet eee omen | ee aoe OFAO MIEN Se oad) avai aw austere Doane eee eee 
| RSE BR RISO ep tet see teal b en aeons OFS 2a: ar sill encbocieess Nome eee | eae 
GOSS ses ee atone 1.45 0.91 1.16 1.10 0.41 DBs 0.50 
99.87 | 100.05 99.93 | 100.28 | 100.64 99.85 99.68 
CEO IG onuntincllcsaoactdlosdocuds (OBA TIRE elie eean le epee aie ns KEN Te mone gel Te 
99.71 
* Specimen from one of the large pebbles in the boulder of Potsdam conglomerate. It was found 
in Franklin county, but the parent ledge is probably in Clinton, 
