Angiosperms (flowering plants) appeared for the first time during the Early Cretaceous; Archaefructaceae, one of the oldest fossil families (124.6 Ma) was found in the Yixian Formation, China.
If the cirque is subject to seasonal melting, the floor of the cirque most often forms a tarn (small lake) behind a dam, which marks the downstream limit of the glacial overdeepening.
