GENERAL MEETING. Wi 
that volcanic rocks predominate around the borders of the 
province. The interior spaces, while not wholly devoid of them, 
show but a very small amount. The region of the High Plateaus 
of Utah, which lies upon the western or northwestern border, 
discloses a very large mass of lavas, erupted chiefly during 
tertiary time, and representing almost continuous activity from the 
eocene to the quaternary. Proceeding southward, we are never out 
of sight of eruptive masses, and in the Unkarets, on the border of 
the Grand Cafion, we find many scores of old and young cinder- 
cones and some considerable lava-fields. In the San Francisco _ 
Mountains we also have a vast field of voleanic rocks, and thence 
southeastward they augment in volume and area until at the 
southernmost extension of the Plateau country they become indeed 
immense. Still following the boundary northward into the Valley 
of the Rio Grande they are found abundant, and a singularly 
interesting field is presented in the neighborhood of Mt. Taylor. 
The speaker was engaged during the past summer in the geological 
examination of the Mt. Taylor district, and it is of the striking 
features there presented that he designs especially to speak. 
Mt. Taylor is an old volcano long since extinct. Its altitude is 
about 11,400 feet above the sea. It stands upon a high mesa, from 
the summit of which it rises as an ordinary volcanic cone of con- 
siderable magnitude—much larger than Vesuvius, much smaller 
than tna. Its lavas are rather monotonous in type, so far as ex- 
ternal appearances are concerned, consisting probably of basalts 
and andesites. The mesa upon which it stands is of great extent, 
being 40 miles long and 25 miles wide. It is composed of nearly 
horizontal cretaceous strata, capped everywhere with basalt or an- 
desite, ranging from 200 to 400 feet in thickness. To the north- 
east and to the south of it are similar high mesas, also capped by 
basalt and andesite, but presenting no great volcanic pile like Mt. 
Taylor. The only features which indicate volcanic vents are barely 
noticeable hillocks, which scarcely affect the evenness of the hori- 
zontal surfaces and which are wholly incommensurate, apparently, 
with the vast lava caps upon which they occur. 
These lavas are all of tertiary age. It would be difficult to say 
to what divisions of tertiary time their activity should be assigned, 
but it cannot have been very late tertiary and it is reasonably 
certain that it cannot have been very old tertiary. In a general 
