GEOLOGY OF GUATEMALA AND SPANISH HONDURAS 517 
recent. The only evidence of pre-Tertiary rocks on the island found 
by the writer was a block of mica schist in the cemetery. The Hog 
Islands, near Nueva Armenia, at the mouth of the Paploteca River, 
are composed, according to Sapper, of mica and graphite schist." 
. Guatemala.—A relief map of eastern Guatemala (Fig. 3) shows 
two remarkable east-west valleys, the Motagua and the Polochie— 
Lake Izabal, separated by the Sierra de las Minas range, which 
follows a curve slightly concave to the north. The region south 
Fic. 4.—Map of the eastern portion of Guatemala 
of the Motagua Valley is formed by the continuation of the Sierra 
de Omoa. The Sierra de las Minas is composed of sedimentary and 
metamorphic rocks of Carboniferous and of pre-Carboniferous age. 
North of Lake Izabal the rugged country of gradually diminishing 
relief is underlain by folded limestones of Cretaceous age. 
Fossils of Carboniferous age were collected by the writer in two 
localities: in the mountains west of Puerto Barrios along the pipe 
line to the reservoir which supplies that town, and on the line of 
the Panzos Railroad, along the south bank of the Polochie River 
near Pancajche, the western terminus of the line (Fig. 4). At the 
former locality poorly preserved fossils were found in weathered 
surfaces of a massive, bluish limestone which is metamorphosed 
and cut by innumerable calcite veins averaging one-quarter of an 
™ Peterm. Mitt., Erginzungsheft 32, Heft 151 (1905), pp. 17-18. 
