A model of the eastern portion of Schroeter's Valley

A relief model of the eastern portion of Schroeter's Valley has been completed using Lunar Orbiter, Apollo 15, and Earth-based photography. The main results derived from this study are as follows: (1) the head of the Valley (the Cobra head) is not a simple crater, but rather a slightly-widened section of the Valley emanating from a shield, (2) the east side of the Cobra head is a very high peak (2.3 km above the surrounding plains) forming part of a broad shield with an average slope of 12 deg, and (3) both sides of the Valley display a raised rim in the region measured. These and other observations indicate the Valley was formed by fluid processes, probably lava, and that the Valley may therefore be a lava drainage channel, the drained lava presumably underlying the more recent Oceanus Procellarum basalts.