Leaves Fossil Site

• General Information
• Directions to Jacks Peak County Park
• Skyline Nature Trail
• Fossil Site Display
• Other Nature Trail Fossil Sites
• Tools and Equipment Required
• Rules and Regulations
• Further Reading

This fossil site is located along a nature hike trail in Jacks Peak County Park of Monterey County in Central California.

This area was under the sea until the Miocene Epoch, at around 12 million years ago, when an island started to appear. Todays Jacks Peak is the tip of that ancient island. That old sea shore is exposed in an outcrop called the Aguajito Shale Formation , where several species of leaves, marine crustaceans, fish and shells have been found.

Jacks Peak is named after David Jacks, a Scottish immigrant of the 1850's that went on to create the famous "Monterey Jack" cheese.

From San Francisco take Highway 101 South until the city of Salinas. Then take Route 68 West for about 20 miles. Just before the city of Monterey, you will see a sign for Jacks Peak County Park. Take it. Go for about 0.5 miles until Jacks Peak Road. Turn left. You will start to climb Jacks Peak and enjoy a beautiful view of the Monterey Bay.

From Los Angeles take Highway 101 until the city of Salinas and then follow the above directions. Jacks Peak can also be reached via Monterey using Route 1.

Once at Jacks Peak County Park, one must park at the west side parking lot - were the Skyline Nature Trail starts (yellow).

The trail is a magnificent display of past and present flora and fauna of the area. You can bird-watch Pygmy Nuthatches, Chestnut-backed Chickadees, Steller's Jays, Darked-eyed Juncos, etc. Also present are native plants such as the Sticky Monkey Flower (Mimulus aurantiacus), the California Sagebrush (Artemisa californica), the Coyote Brush, and others.

The fossils to be seen are several kinds of leaves, shells, and a tiny crab from the extinct Pinnixa galliheri species.

At about 500 yards from the trail head - at marker #4 of the tour - you will encounter the Aguajito Shale Formation were a convenient fossil display has been placed by the County.

The display has specimens of fish (very rare) , crabs from the minuscule Pinnixa galliheri species and sea shells.

Also, with careful looking and some luck, one could see brown fossil leaves exposed in the shale.

A few feet from the display, Coffeeberry trail crosses the Skyline trail. This trail goes downhill for about 2000 feet and exposes more Aguajito Shale strata .

As you walk through Coffeeberry trail, you will see larger fossil leaves and a variety of fossil clams exposed on the shale.

Also, you could encounter pieces of shale fragments containing fossil leaves.

• Only video and/or photo camera. In order to preserve the natural beauty of the park, fossil collecting is prohibited without a special permit - see Rules and Regulations.

All natural features within Jacks Peak County Park are protected and may not be collected or disturbed. A special permit is required for fossil collection in this area. DO NOT collect any fossils without a special permit. Heavy fines are involved for violators. This protected park is a beautiful example of a natural exhibit and must remain UNDISTURBED. For more information call the Monterey County Parks Department at (408)424-8611 ext. 208.

Pinnixa galliheri crab fossils collected at private locations of the Aguajito Shale Formation in the Carmel Valley, are for sale via the Internet at Treasures of the Earth (this link will open a new window - close it come back here). You can obtain very high quality specimens for your collection there.

The following book is recommended for further reading: 

• "A Natural History of the Monterey Bay National Marine Sanctuary" by the Monterey Bay Aquarium and the NOAA, 1997. Rich with maps, photographs, geological diagrams and drawings. A great way to introduce kids to the region's fascinating natural history.

( This publication is just off the press, link to the Monterey Bay Aquarium bookstore for availability information )