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The planimetric shape of a planetary lava flow is often the only quantitative feature that is available from remote sensing data for developing inferences regarding the flow emplacement conditions. A recent study [I] has shown that certain terrestrial lava flows feature margins with a distinct and discernable fractal character, depending on whether the flow was emplaced in the ata or pahoehoe state. In contrast, for some lava flows, the character and length of the margins are completely imposed by the pre-existing topography and terrain, regardless of fluid dynamic and rheologic considerations. The character and length of a flow margin are two diagnostics of the flow dynamics that operated during emplacement. Analysis of these features of planetary flows may lead to new inferences regarding eruption conditions or the independent corroboration of existing quantitative conjectures. It is now well-known [2,3] tha