Cross-hatching at Silver Spur

Abstract

DIAMOND-SHAPED patterns formed by the intersection of two sets of lineaments were reported near the promontory Silver Spur on Hadley Delta, about 20 km south of the Apollo 15 landing site1 (Fig. 1). In discussing possible causes of such patterns, the earlier suggestion2 of hypersonic gas flow was not mentioned by Swann et al.1. Here we point out that omission and also observe that O'Keefe's proposal has recently been put on a more sound basis by Rehfuss's3 calculations on transient lunar winds caused by meteorite impact-vaporization.