skip navigation

Title: A Changing Landscape”;

 With graphic of the Monterey Cypress tree

 “The Bird Trail at Wavecrest

80,000 years ago the spot where you are standing was on the ocean floor.”

 “Today this blufftop sits on a marine terrace that extends to the base of the coastal mountains and includes almost all of Half Moon Bay.”

Photo 1:

Photograph taken from the top of the bluff top you are now standing on.

In the foreground, we see the coastal trail and a small Monterey Cypress tree. The photo is looking North West over the ocean, with Pillar Point Harbor in the distance. 

Photo 2:

An enlarged photo of Pillar Point, where a coastal terrace can clearly be identified in profile.

 “Marine Terraces

 “Marine terraces are level platforms formed by wave erosion in the surf zone. This diagram shows a typical formation of marine terraces.”

Diagram: This diagram represents a cut out section of a coastal terrace.

The diagram shows the ocean on the left with, what looks like two large stair steps coming out of the ocean. These steps are called bluffs. There are two trees on the top of the highest bluff. There are three reference points described next to the diagram.

On the Diagram:

Bullet point 1: Referencing where ocean meets land:

The shoreline and beach are on a platform that is being formed by wave erosion 

Bullet point 2: Referencing the first stair or bluff top:

The blufftop is part of a marine terrace. It sits on an old platform that was revealed over many thousands of years as tectonic plate movements lifted up the land while sea level dropped during a glacial period.”

Bullet point 3: Referencing the top most bluff, furthest from the ocean:

Further inland, there may be old eroded bluffs and covered platforms that are part of another marine terrace.”

Look toward Pillar Point Harbor on your right to view terrace in profile.” 

Photo 3:

Photograph showing the results of erosion on a creek mouth, which is cutting into the blufftop creating a ravine with steep edges several meters high.

 “Erosion

While marine terraces form very slowly, erosion of the blufftops is re-shaping the land much faster. One benefit of this erosion is the sand that it supplies to our beaches. Open blufftop spaces like Wavecrest provide room for the bluffs to erode naturally, while giving people access to the shore to enjoy the breathtaking views of the ocean and beauty of the landscape.”

This portion of the California Coastal Trail sponsored by:

Peninsula Open Space Trust, Coastal Conservancy, Coastside Land Trust, and San Mateo County Parks (with accompanying logos).