The Altamira shale was deposited simultaneously with submarine volcanism about 15 million years ago. Basalt intrusions are extensive along the south and west flanks of the hill. The hot springs mentioned above and the dark basalt platform seen in the pictures above are consistent with the idea that volcanism extended to the surface near White Point. Pillow lava, evidence of submarine volcanism can even be found at the top of the peninsula.
At the bottom of the ramp just before making a sharp turn back toward White Point, there is a recumbant fold. It is difficult to now tell if the fold was orginally a syncline or an anticline. It is so completely overturned. This local folding was probably due to submarine sliding and soft-sediment deformation.
Taking transits or compasses we can determine the strike and dip of the strata or look out at the isthmus on Catalina Island. Students can take a bearing to see that it is due south of this point and that the coast here runs east-west.