Modern volcanoes in the Wudalianchi area erupting during 1719～1721,i.e . the Laoheishan and Huoshaoshan volcanoes, consist of potassiumrich basaltic lava shields and pyroclastic cones. Shieldforming lava flows and coneforming pyroclastic eru pti ons took place successively. The Laoheishan volcano emerged earlier, erupted in grea ter scale and produced more complicated cone structure than the Huoshaoshan. A funne lshaped crater, in the center of Laoheishan twoepisode overlap cone, formed i n the later episode.Its eruption process may be divided into five stages.The Huo shaoshan volcano, a singlecone volcano with a central caldera, underwent three stages.