Geology – five-one-oh

You really have to see Berkeley’s rocks. Ancient rock outcroppings are not so unusual in California, but the way North Berkeley’s neighborhoods integrated the boulders into the built landscape is pretty awe-inspiring.

Indian Rock
A few weeks ago, we took another walk featured in Hidden Walks in the East Bay and Marin, by Stephen Altschuler: Indian Rocks and Four Parks. This one’s become a favorite. The walk starts at the northeast corner of The Alameda and Solano Avenue, on the Indian Rock Path. Indian Rock is an ancient volcanic remnant, composed of Northbrae rhyolite. In 1917, the Mason-McDuffie Real Estate Company donated park parcels around five rock formations to the City of Berkeley, including Indian Rock Park.

John Hinkel Park
After passing through Mortar Rock Park, and walking down San Diego Road, we find ourselves in John Hinkel Park. This park always makes me feel nostalgic for a time when parks were places set in nature, places to explore, places to have a woodland adventure. This seven-acre park was donated to the City in 1919 by John and Ada Hinkel. Before donating the park, the Hinkels added a playground, trails, a huge stone fireplace, and a clubhouse, designed by John Gregg. During the depression, the Civil Works Administration built the stone terraced amphitheater, designed by Vernon Dean. It was home to the California Shakespeare Festival from 1934-1991.

The Great Stoneface Park
Our route leads us down residential streets and hidden paths to the aptly named Thousand Oaks neighborhood. All of the neighborhoods through which we pass feature custom Arts & Crafts homes, many designed by famous architects: Bernard Maybeck, Julia Morgan, and Henry Gutterson.

Our next stop is the Great Stoneface Park featuring another massive boulder, an inviting lawn, oak trees, and a handsome concrete urn. When the Thousand Oaks neighborhood was built, about twenty monumental urns, in the style of Maxfield Parrish, were placed along the streets and walking paths. After a hundred years, only one remains, at the base of Indian Trail. The one in the park is a replica commissioned by neighbors who have organized to recreate this stunning and dramatic tradition.

In Harmony with Nature
The Indian Trail is one of the most rustic and lovely of the hidden paths, with its canopy of oak branches and gates leading to the secret gardens of North Berkeley. The fundamental tenet of the Arts and Crafts movement was to build in harmony with nature. The neighborhoods we pass through blend artistically into the existing landscape. The following quote appeared in an article, “California as a Place for Homes” for the July 1915 issue of California Magazine, by Mark Daniels, the landscape architect who helped layout the Thousand Oaks neighborhood and designed many of the parks and paths we’ve enjoyed on this walk:

“Consider a spot upon the slope of the foothills, where the ground is rendered unavailable for agricultural pursuits by the steep inclines or by the frequent outcroppings of rock, but where gnarled oaks spread their distorted branches and serpent-like roots on every hand. Here is an ideal location for landscape architecture.”

Sources:
Hidden Walks in the East Bay & Marin by Stephen Altschuler.
Berkeley Rocks: Building with Nature by Jonathan Chester and Dave Weinstein.
The historic plaques in Indian Rock Park, John Hinkel Park, and the Great Stoneface Park, City of Berkeley.

Original Urn at the base of Indian Trail

Devil's Slide - Sedimentary layers of shale and sandstone — From Devil’s Slide Trail, we can see sedimentary layers of shale and sandstone thrust up from the ocean floor.

We love going places! In an attempt to reduce our carbon footprint, we spend a lot of our free time traveling local. That doesn’t mean we never fly, but it’s remarkable how much you can learn by visiting places close to home.

Devil’s Slide Trail
This new open space was the first stop on our fall day trip to the coast. Over the years, we’ve been aware of the hellish landslides at this location, sometimes closing Highway 1 for months at a time. On this journey, we learned the area’s geology is the devil causing the slides.

At the north end of the trail are rough sedimentary layers of shale and sandstone that were once part of the ocean floor. At the south end, the cliffs are granitic rock of Montara Mountain. At Devil’s Slide, landslides occur where sedimentary layers were thrust over the granitic rock.

As a result of the landslides, Highway 1 was diverted through the Tom Lantos Tunnels in 2013 and the old highway was converted to this multi-use trail. The views from Devil’s Slide Trail are spectacular but the 1.3-mile walk leads only from parking lot to parking lot. It is a part of the California Coastal Trail and we’re looking forward to the day when it extends from Oregon to Mexico.

This Seafloor Map released by the US National Oceanic and Atmospheric Administration shows the geology behind Mavericks.

Sail Rock from the beach at Pillar Point — Sail Rock as seen from Mavericks Beach at Pillar Point. Mavericks break is about 2 miles from shore, beyond the visible reef.

Mavericks
Geology plays an important role in another coastal site we visited: Pillar Point, site of the famous Mavericks break. Gradual ramping of the sea-floor, plus deeper water on both sides of the ramp are the key ingredients for the magnificent and sometimes malevolent waves.

Here’s my understanding of how this works: As a wave approaches the shore, its base slows as it runs along the rising seafloor while the top of the wave maintains its original speed. This causes the wave to stand up and pitch forward. The long, gradual slope at Mavericks creates an exceptionally tall wave. The wave continues at full speed at the deeper waters on each side of the ramp, allowing the wave to draw additional energy, and creating a wave convergence at the center of the ramp. After winter storms, waves at Mavericks can top out at over 80 feet.

The mild fall weather during our day trip produced little surf but it was a beautiful and adventure-filled day. We walked along Cowell Ranch Beach before stopping at the Ritz Carlton Half Moon Bay for dinner. I’ll tell you what we thought about that, next week.

Sources:
Devil’s Slide Brochure from San Mateo County Parks
Mavericks, California from Wikipedia
Map Reveals Secret of Awesome Mavericks Waves by Phil McKenna from New Scientist