The Paleocene to Miocene Unconformity
A missing part of the geologic record on Pt. Reyes

Following the deposition of the Pt. Reyes Conglomerate (Paleocene) it was significantly eroded (submarine or subaerial?) and younger rocks were deposited on top of it. The evidence includes significantly younger rocks (Drakes Bay Fm) covering these rocks in the Chimney Rock area and it's absence in locations where it would be expected. For example, its absence at the Kehoe Beach area between the granitics and the Laird Formation suggests (unless it was never deposited here) erosional removal. The exposures of Pt. Reyes Conglomerate are also tilted, however evidence of an angular unconformity are not good in exposures that this individual has seen, but it seems reasonable to assume this may have been the case.

(note that the extent to which it originally covered this area is unclear because its absence at any location could mean it was never deposited (hiatus) OR it was eroded following its deposition(vacuity).


Up section to the Laird Sandstone