This member was erupted in the Toledo event, which was named after the Toledo Embayment, a structural feature in the northeast caldera wall which was thought to be the remains of the Toledo caldera. However, more recent work has demonstrated that the Toledo caldera was likely more or less coincident with the Valles caldera. The member is exposed over the entire Jemez area, except within the Valles caldera itself, where it is present only in the subsurface. It is particularly extensively exposed in the Jemez Plateau west of the caldera, but is also exposed across much of the Pajarito Plateau east of the caldera at the bases of its characteristic finger mesas.