The entire sequence of basaltic basement recovered from Ocean Drilling Program (ODP) Sites 1183, 1185, 1186, and 1187 during Leg 192 has undergone low-temperature water-rock interactions. In order to quantify the alteration types and provide a consistent alteration characterization of the samples, alteration and vein logs were compiled for each hole from visual core descriptions made aboard the ship. These logs are meant to provide a method for estimation of downhole variations in basalt alteration and vein abundance/mineralogy. The logs presented in this paper have been slightly modified from their original formats described in the Explanatory Notes chapter of the Leg 192 Initial Reports volume (Shipboard Scientific Party, 2001). These changes reflect the natural evolution of the descriptions during the duration of the cruise. The logs also contain minor additions and omissions that reflect individual variations that could not be accommodated by the log formats. Although every effort to be as quantitative as possible was taken, it is important to note that some aspects of the logs (such as color percentages, thicknesses, and secondary mineral abundances) are estimates based on hand specimen observations.