ROCKS FROM HONDURAS, CENTRAL AMERICA 525 
of coral limestone set in a paste of yellowish white ash. The 
vesicles of basalt are filled with opal, showing that the rock has 
been thoroughly leached since its deposition on a tuff cone in rela- 
tively shallow water. 
Rocks from the Tela district—Near the town of Tela there are a 
large variety of igneous and metamorphic rocks which are more or 
less intimately connected by transitional facies. The igneous 
types vary from granodiorites to gabbros. At the western end of 
the native village the hills are composed of medium- to fine-grained 
augite diorites cut by occasional quartz veins. The diorites are 
composed of basic oligoclase feldspar, biotite, diallage, and accessory 
apatite and magnetite. Three miles west of Tela, Triunfo Point is 
formed by a hill of true diorite which varies greatly in size of grain 
within a few feet. The diorite is black and white in color and 
consists of acid labradorite, common hornblende (pleochroic olive 
green to yellow), and accessory magnetite. Similar diorites are 
exposed in a cut along the Tela Railroad 7 miles west of Tela, and 
in the headland Bishop Point, 5 miles west of Triunfo Point, the 
last rocky point for 70 miles to the west. South of Tela, toward 
the mountains which are locally called the Shark Mountains, 
felsodacites outcrop in Tela valley associated with dioritic gab- 
bros. The felsodacite is dirty buff in color and contains small 
phenocrysts of quartz and larger phenocrysts (3 to 8 mm.) of feld- 
spar. The microscope shows that in the recrystallized mosaic of 
quartz and feldspar myrmikitic intergrowths are common. 
A large number of rocks were collected in the Quemada Hills 
on the west side of Micos Lagoon and about 12 miles east of Tela. 
The accompanying sketch map (Fig. 1) shows the principal points 
visited. Typical diorites, such as compose Triunfo Point, outcrop 
on Minos Hill. Philipe Hillis composed of a sheared granodiorite, 
light gray in color. Under the microscope the rock shows a mosaic 
texture. Quartz and orthoclase with oligoclase are the chief 
minerals, but minute flecks of hornblende are abundant and 
titanite and apatite are present. Apparently intrusive into the 
granodiorite, since it is less sheared, is a basic diorite composed of 
labradorite (Ab,Ans.) and a hornblende which is pleochroic, 
bluish green to light yellow. Apatite and pyrite are also present. 
