The rock record from 234 million to 232 million years ago, captured in these cores from an ancient lakebed in northern China, shows signs of wet weather almost everywhere.
Those in Washington rest on pontoons that are bolted together and anchored to the lakebed with steel cables.
A small village at the eastern end of the Lago de Cuitzeo lakebed; mesquite-grassland.
A village on the south edge of the Lago de Cuitzeo lakebed; mesquite-grassland.
A village on the north shore of the Lago de Cuitzeo lakebed; mesquite-grassland.
In dry years there is little water in the lake, and most of the lakebed is dry; in very wet years the entire lakebed is flooded.
A village on the eastern edge of the Lago de Cuitzeo lakebed; mesquite-grassland.