Interlayered limestone and amygdaloidal basalt flows. Limestone is medium-gray, massive to thick-bedded, and locally metamorphosed to fine- to medium-grained marble. Basalt is dark- to greenish-gray, aphanitic, and contains numerous amygdules. Csejtey and others (1992) suggested that the unit was deposited in shallow water and that the chemistry of the basalts suggests an ocean island shield volcano. Unit is mapped as thrust slivers in Chulitna sequence in the Healy quadrangle (Csejtey and others, 1992) and extends a short distance into the Talkeetna and Mount McKinley quadrangles (Wilson and others, 1998). Included here is a slightly metamorphosed and unevenly sheared sequence of shallow marine, interbedded dark-greenish-gray amygdaloidal metabasalt flows and dark-gray to black argillite and slate. Monotis subcircularis and Heterarstridium sp., of late Norian age, have been collected from argillite (Csejtey and others, 1992)