And what we see is extremely regular thin beds that extend for kilometers and exceptional preservation of soft-bodied material in what's called lithographic siltstone.

我们看到是极其规则薄层，绵延数公里，并且在所谓平版中保了特软体材料。

You're searching for fossils in the Harrison Formation -- a big swath of siltstone, sandstone, and volcanic ash dating back to the Miocene Epoch some 22 million years ago.

您正在哈里森组中寻找化石——一大片、和火山灰，可追溯到大约 2200 万年前中新世时期。