59 GEOLOGY OF 8W. IDAHO AND SE. OKEGON. [bull. -217. 
which it came, a condition illustrated by the Martin lava stream and 
other similar outwellings of lava in mountainous regions described in 
Bulletin No. 199. 
Driblet cones and " ovens."— The extrusion of liquid or highly plastic 
lava from cracks or other openings in the crusts formed on lava, as in 
the craters of certain of the Hawaiian volcanoes, has been described 
by J. D. Dana, a and the hollow cones, towers, etc., produced by drops 
or clots of ejected material which adhered one to another, have been 
designated driblet cones. Interesting examples of structures of this 
general nature occur along the fissure mentioned above, which extends 
westward from the most northern of the Jordan Craters. 
Situated on the fissure referred to are 10 or 12 oven-shaped piles of 
lava clots, some of which are more or less confluent, so that a definite 
count is impracticable. These piles are nearly circular, with rounded 
summits, and range in height from 15 to probably 25 feet, and are hollow 
within. Some of the examples are still unbroken, and are either com- 
pletely roofed over or have rudely circular openings at the top, while 
others are broken and prevent free examination of their interiors. 
One characteristic example, shown in PL XI, A, is about 20 feet high 
on the exterior, between 40 and 50 feet in diameter at the base, and 
within contains a symmetrical level-floored chamber, with dome- 
shaped roof, measuring 14 feet in diameter at the bottom and 17 feet 
in height. The walls of this " oven" are about 12 feet thick at the 
base, and diminish gradually toward the roof, which is from 4 to 6 
inches thick. This beehive-like pile, and others similar to it, are 
plainly of the nature of driblet cones, but on account of their shapes 
may perhaps be termed driblet ovens. Their formation, as has been 
explained by Dana in reference to similar structures observed in the 
Hawaiian Islands, is due to the blowing out of plastic lava from an 
orifice and the piling up of the adhering clots about the place from 
which they came. The hollow chimney-like forms thus produced 
were gradually contracted at the top until, in some instances, they 
became completely roofed over. On the interior of these structures 
the lava hangs in pendant stalactite-like masses, usually of a deep- 
reddish color, and from a few inches to 2 feet or more long. 
Examples of similar driblets cones of smaller size occur on a lava 
flow that came from the Diamond Craters, to be described later, two of 
which are shown on PI. XI, B. Driblet cones are also present at the 
Cinder Buttes, but in this case are chimney-like piles, termed on a 
previous page parasitic cones. One example at the Cinder Buttes, 
however, now partially destroyed, has the oven-like shape so 
characteristic of the example present at the Jordan Craters. 
Lava "gutters."— About the bases of the driblet ovens associated 
with Crater No. 4 of the Jordan series, and also at the east base of 
the crater itself, there are localities where lava flowed in narrow 
"Characteristics of Volcanoes, New York, 1890. 
