Several species of fossils that indicate an age almost precisely at the Cambrian-Ordovician boundary were collected from a limestone olistolith found in turbidite sandstone and shale from Handler Ridge (lat 72°30.5′S, long 167°03′E), an area previously mapped as late Precambrian Robertson Bay Group. The rocks enclosing the olistolith are therefore of this age or younger, not Precambrian, and their presence in this position has important implications to the early Paleozoic history of the Transantarctic Mountains.