Amboy Crater

Two miles southwest of Roy's, a near-perfect black cone rises 250 feet off the desert floor: Amboy Crater, one of the youngest volcanoes in California and among the most symmetrical cinder cones in the country. It was built roughly 79,000 years ago and last erupted something like 10,000 years back, throwing up cinders and pahoehoe basalt in at least four pulses that nested cones inside one another. A breach on the west side is where the final lava broke out and spread, and the flows around the base cover some 24 square miles: lava lakes gone flat and pale with clay, collapsed tubes, spatter cones, and sheets of black rock that soak up the sun and radiate it back. The Bureau of Land Management named it a National Natural Landmark in 1973 for its form and its geology, and it now lies within Mojave Trails National Monument. A trail runs about three miles round trip from the parking area to the rim and down into the bowl; the reward from the top is the whole Bristol Basin at once, the white salt pan of the dry lake, the Bristol and Marble mountains, and the thin line of Route 66 running east to Amboy. This is genuinely dangerous country in summer, when the black field radiates heat past anything a body wants to walk across. October through April is the only sane season, and a gallon of water per person is the rule, not the suggestion.