A lava fracture leads to a crack opening to Mayfield Ice Cave, a series of short entrances that form on the edge of a prominent lava flow stemming from Medicine Lake Volcano, California.  The caves were discovered in 1873 by Mr. J.H. Mayfield searching for one of his lost cattle.  This is the north entrance which has two wooden ladders coming down into a small room that does connect to the room w/ the south entrance.

An old excerpt from the Sacramento Daily Union dated September 24, 1887 reads the following:

Ice Caves.

J.H. Mayfield furnishes us with information concerning an ice cave in the southeastern corner of this county, as follows: The cave was discovered by Mr. Mayfield about fourteen years ago, while hunting for some of his cattle which had strayed away from the band.  About eighteen months ago he returned from southern Oregon and settled at the cave, where he proposes to erect, in the near future, a fine slate-stone hotel, provided the slate of that section works to a good advantage.  There are three caves connected by apertures leading from one to the other.  The first is about thirty feet wide and forty feet long; the second is somewhat smaller, and the third a little smaller than the second.  At any time during the hottest and most sultry weather there is probably never less than one hundred tons of natural ice in sight.  The cave is situated only about forty-five miles east of Sisson, and in the lava beds of historical renown.  Mr. Mayfield has constructed a wagon road through the lava beds, a distance of about twelve miles, at a cost of about $8,000.  During the great Modoc War the ablest and best experts estimated the cost at from $250,000 to $300,000.  Mr. Mayfield attributes his finding of the pass through the beds to the instinct of his lost cattle, which he found there fourteen years ago.  These ice cave are a freak of nature seldom found, and we bespeak for Mr. Mayfield the patronage of many tourists from this point next summer.  - Sisson Herald.