Two small areas of middle Paleozoic limestone were discovered near Gertrude Creek, 16 km north of Becharof Lake on the Alaska Peninsula, during reconnaissance flying as part of the Alaska Mineral Resource Assessment Program (AMRAP) for the Alaska Peninsula. Previously, the only known occurrence of Paleozoic rocks on the Alaska Peninsula was a small exposure of middle Permian limestone on an island at the entrance to Puale Bay (Hanson, 1957). This is the first reported occurrence of middle Paleozoic rocks in what is considered to be a Mesozoic and Tertiary province.