1895I 547 [Crawford. 
seventy miles, on the north side of the Cerro. The altitude 
above sea-level of the ridges or Cimas del Cerro that connect the 
cones and craters varies from 2,000 to 4,800 feet, and that of the 
cones, of which Viejo is the highest, from 2,500 to 5,674 feet.^ 
Proceeding from west to east the names of the craters and 
cones on this mountain range are Chonco, Obraje, San Lorenzo, 
Viejo, Uval, Santa Maria, San Pedro, and Telica, and they are all 
connected by a high ridge. On the east the Cerro is connected, 
by a low ridge seven miles long, with the large oval-shaped 
volcanic mountain and cone Telas, and on the southeast, by 
another low intumescent ridge of about the same length, with the 
extensive mountainous masses of volcanic ejectamenta that border 
the northwestern part of Lake Ilolotlan (Managua) and support 
the large volcanic cone Momotombo, whose ci-ater i-im is over 
6,480 feet above the Pacific Ocean. 
The cones Santa Maria and LTval are still emitting aqueous 
vapors in small but continuous clouds from numerous mud 
springs near their craters. 
The depth and dimensions of the grottoes or caverns or caul- 
drons under the Cerro that contain hydrotherraal vapors^ are 
approximately as follows : from the superior inner surface of the 
cavern up to the plane of the valley on which the Cerro is situ- 
ated, or to about the level of the Pacific Ocean, is about 16,700 
feet; from floor to top of the caverns, usually about 5,500 feet ; 
from floor of cavern up to sea4evel, about 21,500 feet; from 
floor of cavern to apex of the cone Viejo, about 27,760 feet. 
The Cerro is composed of hydrothermal and igneous, exca- 
vated and extruded minerals chemically and mechanically com- 
bined, varying in size from the finest powder produced by attri- 
tion or strong pneumatic forces to large fragments of rocks with 
rounded angles and edges, and in structural features from light 
and porous, as scoriae, pximice, and Pele's hair, to dense and heavy 
doleryte and basalt ; excepting a ridge about nine miles long ex- 
tending from Viejo to Uval, which is composed of sedimentary 
1 These measurements were carefuUy and accurately made for the author in 1891, 
by Lieut. W. B. Fletcher, of the U. S. Navy. Lieut. Fletcher is a constant student, 
especially of sea-margin currents and formations. 
' For the facts in reference to the existence of these caverns and the authors' 
method of estimating their dimensions, see the end of this paper. 
