Seven sites (Sites 991-997) offshore southeastern North America were drilled during Leg 164 (Fig. 1) to provide information on the occurrence and history of gas hydrate in sediment of this region. Sites 991 through 993 were drilled in upper Pleistocene to upper Miocene nannofossil clays and silty clays on the crest and flanks of the Cape Fear Diapir of the Carolina Rise. Site 996 was drilled in upper Pleistocene to lower Pleistocene nannofossil-bearing and nannofossil-rich clays on the crest of the Blake Ridge Diapir, whereas at Sites 994, 995, and 997, Holocene to upper Miocene nannofossil-rich clay and nannofossil clay were drilled over the crest of the Blake Ridge on a transect of holes that penetrated below the base of gas-hydrate stability over a short distance of 9.6 km. Table 1 lists the average depth of water and the maximum penetration of the drill at the seven sites.