PETROGRAPHICAL PROVINCE OF ESSEX COUNTY 481 
TABLE -1I. 
I Il Ill IV Vv VI Vil VIII 1X xX XI XII 
SiO, 77.6% 77-14 76.49 73.93 71.40 70.64 68.88 63.36 67.35 66.60 64.28 63.71 
AO? ; 0.25 0.29 | trace 0.18 ae 0.90 0.19 | trace 0.60 0.76 0.50 | trace 
AO Spee Numa e || Mbeewul) ates on | teas sce san os vane Sieve Ro bere coe uae Bie? 
NO Saageemrnee II.94 12,24 11.89 12.29 14.76 15.34 14.77 16.58 15.05 15.05 15.97 18.30 
Fe,0,. 0.55 0.29 1,16 2.91 1.68 1.83 0.64 0.90 I.23 I.07 2.91 2.08 
FeO... 0.87 1.04 1.56 5S 0.72 I.I0 4.64 3.24 4.76 4.42 3.18 2.52 
Min OMe eee ae. trace trace trace trace trace trace trace trace 0.05 | trace trace trace 
IMPOR ies «sires trace 0.06 | trace 0.04 0.55 0.52 0.37 0.45 0.03 0.36 0.03 0.09 
(CHO ere somes 0.31 0.35 0.14 0.31 0.10 1.24 1.74 1.85 0.55 2.21 0.85 1.18 
Ba Oeeaece cis cevell aces: Aree Reese none mee ada aciscerers sree ieee none none ele 
INGO SRE 3.80 4.64 4.03 4.66 4.79 5.23 3.83 3.907 4.42 4.03 7.28 6.39 
IX6(O) aera aaa 4.98 4:47 5.00 4.63 5.16 3-55 4:07 5-27 6.08 5-42 5.07 6.21 
lal Oh Gure) amen trace trace 0.12 nae Reon 0.14 0.06 0.18 0.16 Bree'l|” kaso 0,09 
Hie © (ignit), .-.- 0.23 0.14 0.38 0.41 1.46 0.38 0.24 0.17 0.17 0.41 0.20 0.17 
EN) ee apse a austen ct fy vaveere ae (ld ite. chose e[hiw wroey ee scaantt istoveree® sige Ncevstecea Mb U dice ssssb || Ptineeee 0,08 fe 
100.54 | 100,66 | 100.77 | 100.91 | 100,62 | 100.87 | 100.33 | 100.97 | 100.45 | 100.33 | 100.33 | 100.74 
Sint (Giisecescens 2.618 650 | 2.642 2.632 2.6096 2.690 | 2,612 2.703 2.686 
ati. To2C: TIC wm lesen ney On| | ware Oy 17°C, r7°C. |ev222@3 ||) 127. 
TABLE I— Continued. 
XIII XIV XV XVI OVI | VT |) XI XX XXI | XXII | XXIII} XXIV 
S103. 63.09 61.05 60,05 59.31 58.77 56.75 51.82 47.12 46.99 46.59 45-32 43.73 
PUO RR Sees sacs 0.45 0.34 O.1I 0.32 0.31 0.30 2.15 3.27 2.92 1.41 1.94 4.23 
ZrO Ree etc 0.06 sapiet la @sacscti| y pee eas O.II sated tee | wecieces eee |S oecved || wanes ame 
WAM OF tore cosacege 18.50 18.81 19.97 22.50 22.04 20.69 17.06 14.43 17.94 17-55 18.99 20.17 
Fe,0, 2.90 2.02 4.32 1.93 1.54 3.52 1.07 3533 2.56 1.68 3.78 4.32 
FeO. 1.36 3.06 1.04 1.40 1.04 0.59 8.60 ay At 7.50 10.46 9-78 6.93 
MnO trace trace 0.79 | trace trace trace trace rire heretic Seidl By cdoe |) come 
MgO 0.16 0.42 0.23 0.17 0.19 OIL 4.87 | 6.05 3.22 7.76 4.68 3-01 
(CAO RGEaSrRneaee I,00 1.30 0.91 0.46 0.74 0.37 8.59 9.63 7.85 10.64 9.19 10.99 
iBaO.... Saheter none seies ee none mone) |) 2-0 aes none ee ferig Meee seeatevens 
INa,O .. 7.25 6.56 7.69 7.98 9.62 Te Ay 3.44 2.58 6.35 3.31 3.78 2.42 
IK \ OBrien 5.23 6.02 3.24 4.08 4.89 2.90 1.77. T,rr 2.62 0.72 2,12 1.45 
B@(r10%);. .... 0.21 are 0.15 0.15 0,07 0,04 O.II Ope || ogee 0,10 0,09 0,08 
BO(ignit).....; 0.62 0.78 | 1.26 Te12 0,90 3.28 0,20 0.34 0.65 0.07 0.31 1,02 
DEO soa sccrcnes ee Cl —or20u | mee oo |r Cl=o0,28 Bee ne OFO4 ul |eraee. neu) emer 0.15 
100.83 | 100.36 | 100,04 99-42 | 100.82 | 100,18 | 100.58 99.85 99.60 | 100,29 99.98 99.40 
Bist oes efvats 2.055 2.708 2.599 2.596 2.474 §3.072 2.919 3.047 2.075 3.058 
z2°C, Bes T2C, |) 1° e2ue. 12° Toca err Cu | petra Oon| ger reG. 
Granite. Rockport. XIII. Pulaskite. Salem Neck. 
Aplite (mean). Bass Rocks. XIV. Solvsbergite. Coney Island. 
Paisanite. Magnolia. XV. Tinguaite. Gale’s Point. (Eakle.) 
Granite. Quincy. (Blue Hills.) XVI. Foyaite. Great Haste Island, 
Keratophyr, Marblehead Neck, XVII. Foyaite. Salem Neck, 
Rhyolite. Marblehead Neck. XVIII. Tinguaite. Pickard’s Point, 
Quartz-syenite-porphyry. Squam Light. XIX. Diorite. Marblehead. 
Nordmarkite. Wolf Hill. XX, Diabase. Rockport. 
Enclosure in Granite. Rockport. XXI. Essexite. Salem Neck. 
Akerite. Gloucester. XXII. ‘‘ Camptonite.”” Salem Neck, 
Sdlvsbergite. Andrew’s Point, XXIII. Hornblende Gabbro, Salem Neck. 
Pulaskite. Salem Neck. XXIV. Gabbro. Nahant. 
