When time began in this part of the East Bay, the people led a lifestyle based on the plants and animals. The Ohlones didn’t build with brick or mud and didn’t rely on pottery, so the soil below was not a concern. Their needs for good clay were modest.
When the Spanish took this land, they found the clay soil excellent for their purposes. “The habitations of these people,” wrote Joseph E. Baker in his 1914 history of Alameda County, “were fashioned of large, sun-dried bricks made of that black loam known to settlers in the golden state as adobe soil, mixed with straw, measuring about eighteen inches square and three in thickness, these being cemented with mud, plastered within with the same substance and whitewashed when finished. . . . When completed these dwellings stood the brunt and wear of many decades of years.”
Some of the adobe bricks from the original Peralta hacienda are preserved in Dimond Park.
Like every frontier settlement, Oakland bootstrapped its way to civilization by using what it had on hand. The very first Gold Rush visitors dug into the ground for resources, looking for what served them in their homelands whether it was good farm soil or something more specialized. In 1850, a French man by the name of Romby located decent clay along the shore of Lake Merritt in Adams Point, and with the help of fellow immigrant George LaFleche started a small brickworks there. The exact location is now lost, but I’ve seen the same promising material in excavations at Lakeside Park. It’s marine clay from the days when the sea level was extra high.
Other brickworks (“Brik Kilns”) sprang up in the early 1850s in the Grand Lake neighborhood, as seen in the Kellersberger map surveyed in 1853. I place this between Cheney and Wickson Avenues, behind the Grand Lake Theater.
There would have been lots of firewood handy for the kilns in Indian Gulch — one reason all of Oakland and Alameda’s oak forests disappeared within a couple of decades.
Romby soon relocated to better raw material on the west side of the lake where the Kaiser Center building sits today, then down to the Melrose area at the foot of High Street, where “Romby’s brickyard” was named as a boundary landmark when the Town of Alameda incorporated in 1854. A court case in 1885 referred to it as “the old brickyard house,” signifying to me that the business had closed shop, but by then it had been memorialized in the name of Brick Yard Slough.
The Remillard brothers (French Canadians) had brick kilns in East Oakland in the 1860s, but as their fortunes rose and the railroads made transport easier, they opened plants near Pleasanton, San Jose and Greenbrae. Oakland was not perfect territory for brickmakers, but it was good enough for small companies making serviceable products.
Premium potteries — making tile products and ornamental objects — found Oakland fertile ground, using coal from Pittsburg and high-grade clay from the Ione area of Amador County, and Oakland became a center of the architectural tile industry.
Oakland Geology 
10 February 2022 at 2:39 pm
I found an old brick at my grandparents’ house in San Francisco stamped “Ione”. Now I know why.
18 January 2022 at 8:04 pm
The Berryessas and Peraltas came on de Anza’s second trip to Alta California in 1776 to build a Presidio at Yerba Buena. The Berryessa son married the Peralta daughter, and the Peralta daughter married the Berryessa son. They traveled in de Anza’s party on “The Old Santa Fe Trail.”
Later, in a matter concerning the ownership of Capay Valley, Reyes Berryessa was executed by the US Army scout Kit Carson on the orders of General John Fremont. This heinous act is cited as ruling Fremont unfit later in his bid as President of the United States.
My great-great-grand-father Julian Berryessa married Emilyanna Pena. Their home is now the Pena Adobe park.
To the best of my knowledge, no descendants of the Berryessas live on what was their 35,000 acre land grant, which was stolen by American squatters, successfully defended in court, yet lost to legal fees.
There it is, the lawyers always win.