Cr osby.] 
282 
[November 2, 
ture, %. e., that the texture of any rock may be correctly deter- 
mined without the use of a microscope. We may say, then, that 
in every case the constituent particles are either macroscopic or 
microscopic, i. e., that they are either visible or invisible to the 
naked eye. 
CLASSIFICATION OF TEXTURES. 
1 
Macros 
in whic 
they 
c 
Fragments 
'he constituent ] 
are e 
>copic, c 
;h case 
are 
>r 
Crystals. 
^articles of roc. 
ither 
>r Micro 
in which ca 
under the 
0 
Visible 
cs 
scopic, 
se they are, 
microscope, 
r 
Invisible. 
Primary 
Textures. 
Fragmental. 
Crystalline. 
Compact. 
Vitreous. 
Secondary Textures. 
<D 
4-> 
at 
G 
a 
Banded. 
Banded 
Fragmental. 
Banded 
Crystalline. 
Banded 
Compact. 
Banded 
Vitreous. 
Schistose 
or Shaly. 
Shaly 
Fragmental 
Schistose 
Crystalline 
Shaly 
Compact. 
Porphyritic. 
Porphyritic 
Crystalline. 
Porphyritic 
Compact. 
Porphyritic 
Vitreous. 
Concretionary. 
Concretionary 
Fragmental. 
Concretionary 
Crystalline. 
Concretionary 
Compact. 
Concretionary 
Vitreous. 
Vesicular. 
Vesicular 
Compact. 
Vesicular 
Vitreous. 
Amygdaloidal. 
Amygdaloidal 
Compact. 
Amygdaloidal 
Vitreous. 
Tufaceous. 
Tufaceous 
Compact. 
Friable 
or Earthy. 
Friable 
Fragmental. 
Friable 
Crystalline. 
Earthy 
Compact. 
