A Brief Guide to the Parapet View, Sinnott Memorial, Crater Lake National Park by John Campbell Merriam, 1938
View 6: Latest Stage in Forming in the Crater Lake, Eruptions Producing Wizard Island and Two Other Cones
If the lake were removed the crater would be seen as a relatively flat-floored cavity extending as a maximum about 2,000 feet below the present lake surface. In this great depression Wizard Island would appear as one of three small volcanic cones produced by pouring out of lava and cinders in the last period of volcanic activity. Forming of the present floor probably involved many stages, during some of which the cauldron-like crater may have been occupied by wide stretches of molten lava, as in the “lake of fire,” at Kilauea, in Hawaii.