278 
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BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
dla bis. Diabase or coarse basalt. This probably Culebra 
Summit — 41a. 
41.1. White and red banded rock. Isotropic in slide. Sili- 
cified or cherty. 
41.2 and 41.3. Porphyrite. 
Beach drift at Market Front, Panama. A fine grained green- 
ish diabase porphyrite. 
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Culebra, Isthmus of Panama. Dense greenish eruptive rock 
diorite porphyrite. 
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Pebbles from Cut 1 at Culebra section. (See page 195.) 
. Chert. 
. Cherty tuff (with feldspar fragments). 
. Silicified tuff with large feldspar fragments. 
. Fine grained black shale siliceous with feldspar fragments. 
Gravels at junction of the River Chagres with the Obispo, Isth- 
mus of Panama; brought down by river from unexplored interior. 
1; 
. Green rock containing granite fragments; fine grained augite 
Granite. 
porphyrite. 
. Granite. 
. Fine grained quartz diorite. 
. Decomposed porphyrite. 
. Granite. 
. Basalt. 
. Dasalt. 
. Very much altered quartz porphyry or rhyolite. 
. Quartz diorite porphyrite. 
. Augite andesite. 
. Epidotized diabase-porphyrite. 
. Black cherty siliceous shale. 
. Pasalt. 
. Greenish porphyrite. 
. Dark gray augite porphyrite. 
. Quartz porphyrite. (See 27.) 
. Glassy hypersthene-andesite. 
. Decomposed quartz-porphyry. 
. Probably chert. 
. Granite. 
. White granophyric quartz-porphyry. 
. Granite. 
