Fossils

Fossil log
Fossil log
Fossil worm tubes in Delmar Formation
Fossil worm tubes in
Delmar Formation

Most of the fossils in the Reserve are found in the Delmar Formation at the bottom of Fossil log on the beach cliffs. The oyster beds are the most obvious. The siltstone layers have other shells and casts of tubes made by burrowing animals. Fossil logs show as holes in the rock with carbon in the center and sulfur staining the surrounding rock.

Cast of tree root in Torrey Sandstone
Cast of tree root in
Torrey Sandstone

In the Lindavista Formation, in the roadcut between the Fleming Trail and High Point, is the cast of a tree root sticking out of the rock about two feet. It looks much like the dead roots of Torrey pines near it. A tree died and rotted away, then the root hole was filled by the same gray sand that filled nearby cracks in the rock. The gray filling is more resistant to erosion so remains after the red rock erodes.

In the Bay Point Formation, on the Beach Trail near the beach, is a layer of shells in the soft rock. If you walk up the Broken Hill Trail, you will soon see the top of the shell layer. Since these Pleistocene fossils contain about 95% shells from modern species, it is difficult to tell shells on the surface from those in an Indian midden of modern shells. These shells have been dated at 120 thousand years old.

Fossil shell layers
Fossil shell layers

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