Even before I knew what it really was, this short pier at Middle Harbor Park stood out.
This is clearly not a typical groin or breakwater, something that is dumped into place, but a carefully laid work of drystone masonry. It feels absolutely solid to walk upon. And then there are the rocks in it, a rich assortment of large and pristine Bay area specimens. There are tuffs composed of volcanic pyroclastic flows,
colorfully metamorphosed volcanics,
and other metamorphics whose colors could inspire a fabric maker.
Also sandstones and even a few ringers of Sierran granitic rocks, perhaps from the old quarries of the Rocklin area. But it’s not typical of a modern marine rockwork—those use stone trucked in from a single quarry to save money and control the quality.
An interpretive sign explains that it’s a replica of the old “training wall” on the north side of the shipping lane to Oakland Inner Harbor, where the signature gantries load and unload big freighters. Training walls are jetties designed to turn a shipping channel into a flume during ebb tide, keeping the bottom clear of mud. The walls were built around the 1880s, using shoreline quarries around the Bay and shipping the rock here by barge. That explains the unique variety and distinctive regionality of the material.
The north training wall was removed when the shipping lane was enlarged in 2001, but they saved some of the stones. Masons installed them over a core of rubble, and here they are. The south training wall remains in place.