KINDS. 
BASIC 
Silica 45 to 52 per cent. 
(oe 
INTERMEDIATE 
KINDS. 
ACID KINDS. 
Silica 60 to 78 per cent. 
oe 
Summary tabulation of the 
eruptive rocks of the Kewee 
Coarse-granular kinds, 
Olivine-gabbro (B 1). 
Olivine. 
Anorthite. 
Diallage. 
Titaniferoas magnetite. : 
Non-orthoclastic, olivine-free gabbro and diabase 
(in part only) (B 1). 
Anorthite or labradorite. 
Diallage or augite. 
Titaniferous magnetite. 
Anorthite rock; a special phase (B 4). 
Silica 45 to 48 per cent. 
Fine-granular kinds. 
Grading by increasing fineness of 
| grain and loss of diallagic cleavage 
in the augite, which remains coarser 
than the other constituents, into 
a 
Olivinitic diabase and melaphyr (‘lus 
tled” rocks), B 6 (in large part). 
Anorthite. 
Olivine. 
Augite. = 
Titaniterous magnetite. 
Pseud-amygdaloids a special phase. 
Grading by increasing fineness of 
grain into —> 
oe pide ase diabase (in small pa 
). 
Labradorite. 
Augite. 
Magnetite. 
Pseud-amygdaloids a special phase. 
Grading by loss of olivine, decrease in basicity 
of the plagioclases, and, in some kinds, by 
addition of orthoclase, into 
| 
Grading by loss of olivine and decrea: 
sicity of plagioclase, into 
| 
Non-orthoclastic olivine-free gabbro and diabase 
(in part only) (B 1). 
Labradorite. 
Diallage or augite. 
Titaniferous magnetite. 
Orthoclase-gabbro (in small part only) (B 2). 
Labradorite or oligoclase. 
Orthoclase. 
Diallage and augite. 
Titaniferous magnetite. 
Apatite, uralite, common accessories. 
Uralitic gabbro (B 2). F 
Hornblende-gabbro (B 3). } Special phases. 
Silica 48 to 52 per cent. 
Grading by increasing fineness of 
grain into ——> 
“ Ordinary-type”’ diabase (the larger pa 
Labradorite or citmealegne ces 
Augite. 
Titaniferous magnetite. 
Pseud-amygdaloids a special phase. 
Grading by decreasing basicity of plagioclase, 
increase of orthoclase, and introduction of 
secondary quartz, into 
| 
Grading by decreasing basicity of f 
into 
< Orthoclase-gabbro (the larger part) (B 2). Gradation forms not known, into —>| “Ordinary-type” diabase (in small part o1 
s Oligoclase. Oligoclase. 
Ps Orthoclase. Orthoclase possibly in a few kinds ( 
2 Diallage. Augite. 
= Augite. Titaniferous magnetite. (These ro 
© Titaniferous magnetite. never been found to contain over 
£ Apatite, uralite and secondary quartz, very per cent. silica—rarely so muc 
3 - common BecerneeS a5 Pes eben by qnarte eaillbsae 
ralitic orthoclase-gabbro (B 2). } . ans seud-amygdaloids a special phase. 
S| Hornblende-gabbro (B 3). Special phases. 
a 
Grading by decrease of augitic constituent, and Gradation phases not known, into 
increase of orthoclase and of quartz, into 
= Augite-syenite (in part) (A 3). Grading by increasing fineness of | Fine-grained augite-syenite (A 3). 
3 Oligoclase. grain, into —> Orthoclase. 
R Orthoclase. Oligoclase. 
= Augite (very subordinate). Augite. 
S Verrite and abundant quartz characteristic Ferrite. 
2 accessories. Secondary quartz. 
3s 
a 
a] 
Grading by decrease of oligoclase and great in- Grading by increasing amount of quart 
crease of quartz, into 
= | Augitegranite (A 4) and granitell or granitic | Grading by increasing fineness of | Fine-grained granitell or granitic porphy 
= porphyry (A 3) (in part). grain, into —> (in part). 
9 Orthoclase. Orthoclase. 
2 Oligoclase (not always present). \ Oligoclase. 
ie Quartz. Quartz. 
2 Augite (always more or less thoroughly al- Augite (very sparse, altered to 
3S tered to ferrite or hornblende and very chlorite, or uralite). 
= sparse). Ferrite. 
= Secondary quartz. 
= 2 
= A 
Trace page 126, Vol. V, Irving. 
