The Morawan Formation is a Chattian age siliceous marine geological formation of the Oligo-Miocene Japanese Kawakami Group of eastern Hokkaido prefecture.

[1][2][3] The formation is fossil rich and contains source units where toothed baleen whales (Aetiocetidae) and Desmostylians have been discovered.

[4] The Morawan Formation is a very siliceous unit containing hard platy shales interbedded with tuffaceous mudstones and sandstones, and some pumice.

The unnamed lower member is a hard platy shale alternating with beds of tuffaceous mudstones and sandstones, the Kamirawan member is a tuffaceous sandstone with pumice, the Lower Hard Shale is a very siliceous hard shale with tuffaceous sandstones and mudstones, and the Middle Hard Shales and the Upper tuffaceous siltstone are similar.

[5] Fossil species from the Morawan Formation include: