Leg 183 provided an exceptional opportunity to examine a wide variety of mafic lava flows in unprecedented detail. This allowed the development and application of a systematic lava flow characterization scheme. Although this technique needs additional work, especially for the identification of slab pahoehoe, it is more than adequate to identify the types of lavas found during Leg 183 and to assign confidence values to the identifications. Whereas about half the lava flows were similar to lava flows found in Hawaii, just over 50% were of a different morphology. This lava type has been named "rubbly pahoehoe" and shares characteristics with both aa and pahoehoe lava flows.