ROCKS FROM HONDURAS, CENTRAL AMERICA 527 
undoubtedly derived from the metamorphism of diorites. They 
are composed of andesine and a hornblende which is pleochroic 
light yellow and olive green to bluish green. Associated with the 
hornblendites are dioritic biotite orthogneisses. 
Along the Tela Railroad 14 and 16 miles east of Tela sedimentary 
quartzites and gneisses are exposed, while at Uraca, 56 miles south- 
east of Tela by rail, medium- to coarse-grained tonalites composed of 
quartz, oligoclase, and a little hornblende outcrop over a large area. 
The tonalites extend eastward past San Pedro Sula. 
Rocks from Puerto Cortez and vicinity.—The region about Puerto 
Cortez has been built by shoreward currents and by the vegetation 
in swamps. But across the bay the waves have exposed.a series of 
Tertiary sandstones which are greenish gray when fresh, but which 
oxidize to a limonitic clay. They are composed of very fine grains 
of quartz and muscovite mingled with an equal proportion of 
glauconite particles. The rock is gritty and friable and hence is 
quite like a typical green sand both in color and texture. 
Proceeding southward along the Honduras National Railroad 
from Puerto Cortez volcanic rocks similar to those on the island of 
Utilla overlie sheared felsodacites at Chameleconcito. The par- 
ticular specimen collected is a dense porphyritic basalt composed 
of large phenocrysts of labradorite, olivine, and augite set in a 
cryptocrystalline groundmass of the same minerals associated with 
magnetite dust. 
At Baracoa specimens of an even, fine-grained, dioritic gneiss 
were found associated with an actinolite gneiss composed entirely 
of actinolite in rosettes of radiating fibers. Near La Pimienta 
there are chocolate-colored felsites which show a flow structure and 
carry small phenocrysts of oligoclase feldspar. When decomposed 
they form a residual clay very free from iron compounds. ‘They 
have not been sheared or folded like the other felsites described 
because they are much younger—probably post-Cretaceous. 
Rocks from Landslide Valley, San Pedro Sula.—On account of 
residual soils fresh rocks are seldom found in Honduras. An 
exception to this rule occurs, however, in the valley southeast of 
San Pedro Sula conspicuous for the large bare face of a moun- 
tain left by a landslide. Here bronze-colored biotite schists are 
