J ernes — Albuquerque, N. Mex. — Reagan. 105 
point 'South of Albuquerque north by the way of Cochiti be- 
yond Abiquiu, in Rio Arriba county, a distance of 100 miles. 
On this dike there are several groups of volcanoes, some of 
which are : the Albuquerque, the Bernalillo, and the San Fel- 
ipe volcanoes. 
The Albuquerque Volcanoes. — Across the Rio Grande to 
the west of Albuquerque about six miles, six volcanic plugs 
arranged in a north and south direction project above the mesa. 
From these craters a lava flow seems to have spread out in all 
directions. It is black vesicular basalt, and covers an area of 
about thirty six square miles. Its thickness, is about 20 feet. 
The lava rests on Eocene strata. 
The Bernalillo Volcanoes. — The Bernalillo volcanoes are 
situated to the west of the Rio Grande at its confluence with, 
the Jemez river four miles to the northwest of Bernalillo and 
twenty miles to the north of Albuquerque. Craters are found 
on each side of the Jemez ; but the one to the south of the river 
is the most conspicuous. The loose Eocene strata have been 
removed from it and the plug of the volcano or "neck" now 
protrudes above the general level of the surrounding country. 
From the plug dikes radiate, giving a rib-like structure to the 
exposed surface. The lava flow, to the south of the river Jemez 
has "been removed for the most part ; but to the north, the lava 
sheet is thick and continuous with the lavas poured out by the 
San Felipe volcanoes. The lava is black vesicular basalt the 
same as that of the Albuquerque volcanoes. 
These volcanoes are of interest because their lavas pouring 
into the old channel of the Jemez river brought about a per- 
iod of damming, thus forming the Pleistocene lake of the lower 
Jemez, previously mentioned under the head of "Pleistocene 
Deposits in the Jemez valley." 
The San Felipe Volcanoes. — The San Felipe volcanoes are 
many in number. Thirteen were visited by the writer and Dr. 
G. B. Haggett in one day. Most of the pot-like craters are 
small ; but some of them are of large size. One in particular 
that we measured was one-half mile in diameter and another 
was still larger. The walls of the half mile crater are still in 
existence. The walls within the depressions were fovmd to 
be glazed and blackened and to be composed of sand mixed 
with fragments of basalt. The remains of most of the volcan- 
