Cryptomaria are buried mare basalt lavas. They are indicated by impact craters that excavate below surface bright materials (typically dustings by basin and crater ejecta) to bring up dark material. These dark halo craters often look similar to volcanic dark halo craters (as in Alphonsus) but they are not associated with rilles or other volcanic features. Cryptomaria that are not buried deeper than a few tens of meters can also be detected with 70 cm radar which penetrates the surface debris and bounces off the underlying basalt surfaces. Hartmann and Wood, 1971 provided an early description of crytomaria, and Jim Head and his student Irene Antonenko studied them in detail.