As seen here.
SAN FRANCISCO — Scientists have discovered one of the world's weirdest volcanoes on the seafloor near the tip of Baja, Mexico.
Unlike most deep-sea basalt lavas, the rhyolitic lavas on the Alarcon Rise were very thick and pasty, like chunky peanut butter. As they emerged from the underwater volcano, they formed large, angular blocks, some of which tumbled down the sides of the volcano, eventually covering the sides of the dome in talus.
CREDIT: (c) 2012 MBARI