Mud cracks in an arroyo near San Ysidro
Image taken: 10/10/2021by: Adam Read
(WGS 84 or NAD 83)
About this image
Ripple marks are preserved on thin clay sheets that are now separated by mud cracks. These features formed after a recent flash flood event, but sedimentary structures like these are often seen in ancient rocks. This illustrates the principle of uniformitarianism, often summarized as "the present is the key to the past".
Image posted: 12-17-2021