🪨 The Rockaway Beach, Pacifica Quarry

Early Days: Native Use & Spanish Era

Long before big industrial machines showed up, the area around what is now the Quarry was important to the local Ohlone people. They mined the limestone simply but effectively for trade, construction and decoration.

Then, in the 1700s, the Spanish arrived. In 1776, the settlers at the Presidio of San Francisco began using limestone quarried near Rockaway for building and whitewashing purposes. When you whitewash a building or fort, you use lime — made by heating limestone — to create a bright, reflective finish that also helps protect walls. The Rockaway limestone supplied that. The quarry’s early role is less glamorous than later industrial operations, but it shows the deep roots of that landscape in Pacifica’s and the Bay Area’s history.

Industrial Rise: Early 1900s & San Francisco Rebuild

From the late 19th into the 20th century, the quarry’s importance grew significantly. After the 1906 San Francisco earthquake, much of San Francisco needed rebuilding — and rock and limestone from the Quarry came into play.

The limestone at Rockaway was used for multiple construction purposes:

• Whitewash and mortar: The same early uses continued but on a larger scale.

• Ballast and infrastructure: The Quarry provided ballast rock for the trackbed of the Ocean Shore Railroad, the coastal rail line built around 1907.

• Aggregate and foundation materials: As commercial operations expanded, crushed limestone and aggregate from the Quarry were used in local roads, rail, and rebuild-efforts in the Bay Area.

So in short: the Rockaway Quarry wasn’t just a scenic hole in the hill. It played a tangible role in rebuilding parts of the Bay Area after disaster and in laying the physical rails and roads of the early 20th century.

The Geology: Why This Limestone?

What makes the rock here worth digging? It turns out the limestone in this zone is part of something called the Calera Limestone, a special type of rock found in the coastal area near Pacifica.

Geologists have determined that this limestone formed between about 88 and 105 million years ago in the Cretaceous period, likely on a sunken volcanic ridge far out in the Pacific. Then tectonic movement brought it to the North American continental edge.

The bottom line: what’s under the Quarry today is both historically useful and geologically special.

Decline & Closure

By the mid-20th century, demand shifted. The Quarry changed hands several times: from the Tobin family to Hibernia Bank, then to Howard Marks, then to Rhodes & Jamieson, and finally to Quarry Products Inc.

Mining operations ultimately ceased in 1987.  Exhausted easy reserves, change in construction materials, environmental concerns, and shifting industrial economics.

After closure, the land was left with steep, unstable slopes, bare rock faces, and disturbed terrain.

What Was the Limestone Used For — A Closer Look

Let’s zoom in on some of the more specific uses of the quarry’s output, so you can see the scale and connection to our region:

• Whitewash and mortar for the Spanish-era Presidio and missions: The early use may seem small by today’s standards, but it tied this remote coast site to the major colonial installations in the Bay Area.

• Ballast for the Ocean Shore Railroad: The rail line built along the coast used rock from the Quarry to build its foundation, helping to carry trains up and down the peninsula.

• Rebuilding San Francisco after the 1906 earthquake: The Quarry’s limestone and aggregate were used in rebuild efforts—roads, foundations, structural concrete.

• Concrete aggregate and industrial production during WWII: During the war, the quarry ramped up production of high-grade limestone for concrete and infrastructure needs.

In essence, the Quarry bridged local resources to large-scale Bay Area development. It was contributing to San Francisco’s infrastructure and California’s war-time industry.

The Site Today & What’s Next

Even though mining stopped decades ago, the Quarry remains a big part of Pacifica’s landscape and conversation. The land is disturbed, has significant reclamation needs, and sits at the edge of the coast in a landscape of both natural beauty and industrial legacy.

There are plans and discussions about how to reclaim the site: grade the slopes, replant native vegetation, create wetlands, trails, and open-space access.

Meanwhile, any future development is weighed heavily against environmental concerns, community impact, traffic, and respecting the site’s history.

Why the Pacifica Quarry Story Matters

Pacifica’s Quarry isn’t just a patch of land near the coast. It’s a piece of our town’s ongoing story.

The way this site has been used, debated, and protected over the years says a lot about who we are as a community and how we balance progress with preservation.

A legacy written into the landscape.
The Quarry’s history shapes how we view development along our coastline. Each proposal and plan — whether realized or not — adds to our understanding of what Pacifica values: open space, access to the ocean, and a character that still feels small-town by the sea.

A reflection of local identity.
This land has been more than a project site. It’s been a mirror for the conversations we keep having about Pacifica’s future.

For longtime residents, it’s a reminder of how far we’ve come. For newcomers, it’s a glimpse into the passion and persistence that define this community.

A conversation that connects us all.
Even when the Quarry sits quiet, it sparks discussions about environment, zoning, and the balance between preservation and progress. Its story is a thread that weaves through Pacifica’s history; connecting past decisions with the choices we’ll make next.

📚 Sources

1. Rockaway Quarry (Wikipedia Overview)

2. Rockaway Beach, Pacifica – Local History & Railroad (Wikipedia)

3. Calera Limestone: A Gift from the Ancient Pacific – KQED Quest

4. Abandoned Mines: Rockaway Quarry Reclamation Project – GeoCon, Inc.

5. City of Pacifica Opens Public Comment on the Rockaway Quarry Reclamation Plan & Trail System – Coastside Buzz