-NOTES ON A COLLECTION OF ROCKS FROM 
HONDURAS, CENTRAL AMERICA 
WILBUR G. FOYE 
Wesleyan University, Middletown, Connecticut 
Introduction.—The rocks described in this paper were collected 
by Dr. Sidney Powers during the summer of 1917 from the province 
of Atlantida, northwestern Honduras, and from the outlying island 
of Utilla. A summary of the general geology of the region is given 
in the paper preceding this by Doctor Powers. A high range of 
mountains composed of batholithic intrusions of granodiorites, the 
Sierra de Pija, extends along the northern border of Honduras and 
sends radiating spurs toward the coast. Most of the rocks were 
collected from stream valleys cutting the northern slopes of these 
mountains. 
The chief centers from which collections were made are Tela, 
Puerto Cortez, San Pedro Sula, La Ceiba, and Nueva Armenia. 
These towns are shown in Fig. 2 of the preceding article. The 
island of Utilla lies 20 miles off the coast and is one of the Bay 
Islands. 
Rocks from Utilla Island.—Utilla is largely fashioned from 
Quaternary basalts. The basalt which occurs back of the town 
of Utilla is gray black in color, some of it dense, some of it vesicular. 
In certain varieties the feldspars abound; in others augite and 
olivine phenocrysts are more abundant. The groundmass has an 
ophitic texture and is composed of andesine, augite, and olivine. 
The feldspar phenocrysts are zoned and have the composition of 
basic andesine and medium labradorite. Basalts from Stuert Hill, 
which is probably the center from which the flows came, are simi- 
lar to the type just described, but are more vesicular and im- 
pregnated by calcite. Stuert Hill is composed principally of 
agglomerate. 
Pumpkin Hill, 13 miles southwest of the town Utilla, is under- 
lain by tuff composed of coarse bits of lapilli and angular fragments 
524 
