Union Brick Company
In 1904, John Willard Rice, born in Iowa on January 10, 1879,
established a brick manufacturing firm at the foot of 23rd
and Pierce streets, San Diego. The Union Brick Company was organized
with John Rice as president, William C.S. Cross as
vice-president, and Eva E. Rice as secretary and treasurer.
John and Eva Rice were married in 1907. Surface clay was
obtained on the property to make common brick until about
1912, when the company moved its operations to Rose Canyon,
10 miles north of San Diego. The Union Brick Company
purchased the former property and plant of the Sunnyside
Brick and Tile Company, consisting of 220 acres of patented
land. The plant's leaning smokestack was a landmark for
many years for motorists passing by on Highway 101.
The clay mined at Rose Canyon was part of the Rose Canyon shale member
of the Eocene La Jolla formation. The first pit mined was
near Elvira Station on the Santa Fe Railroad. The plant
was also located there until the pit was abandoned in
1941. The plant was moved about 2.5 miles south where
the company opened a second pit on the west side of Rose
Canyon. The West pit closed in 1947, and a third pit
was opened on the east side of the canyon. The East pit
was worked until the operations closed in 1965. Clay
was mined during the 1920s by Fordson Tractors and
scrapers, which dumped the material into a chute at the
bottom of the canyon.
In 1925, the plant consisted of a dry pan and two brick
presses for making dry-pressed bricks. They also made
sand-molded common brick. Operations described in 1963
stated that the clay was reduced to minus 1/4-inch in a
primary crusher, ground in a dry pan, and delivered to
a screw-type pugging and extrusion machine. Barium
carbonate was added to the water to reduce scumming in
the finished brick. A vacuum of 24 pounds per square inch
was used to remove any air trapped in the mix. The
continuous bar of clay extruded from the pugging machine
was cut by wire cutter into bricks. Different dies were
used to produce the various shaped bricks. It took five
to six weeks for the wet bricks to dry in the sun or a
shorter time in fan-ventilated sheds and hot air dryers.
After drying, the bricks were fired in field (scove)
kilns for six days or for 24 hours in a shuttle kiln.
Oil was used for the fuel and the plant was powered by
electricity. The plant had a capacity of 80,000 bricks
per eight-hour period.
The bricks produced by the Union Brick Company varied
over the years by the change in location of its clay pits
and the type of brick processes used. The bricks made
at its 1904 to 1912 plant in downtown San Diego was
probably a sand-molded common red brick. After 1912,
red common dry-pressed brick and building tile were
added using Rose Canyon shale. The sand-molded brick
made in Rose Canyon very likely differed from the
earlier San Diego sand-molded brick, which I have no
example yet to describe. It is not known exactly
when the company began to produce the different shaped
bricks. These include the smooth or scratch face brick
Standard (8 x 3 3/4 x 2 1/2), Norman (11 1/2
x 3 1/4 x 2 1/2), Oversize (11 1/2 x 3 1/4 x 3 1/2), and
Brik-Blok (11 1/2 x 5 1/2 x 3 1/2 and 15 1/2 x 7 1/2 x
The Union brick plant closed about 1965. The buildings
and the leaning smokestack were eventually razed and the area has
been restored back to its natural state in Marian Bear
Common brick is orange to red and mostly uniform in color.
The edges are straight and dull. Corners are dull or
broken. Sides and ends are mostly unmarked with minor
cracks. Top face is uneven, highly pitted, with large pits up
to 1 1/2 inches across, and has a longitudinal strike. Stack
indentations may be displayed on the faces.
Bottom face is flat with the initials of the company centered
in a beveled, rectangular frog. The letters are raised, thin,
and span 3 1/2 inches. The block letters U, B, and C are 1 1/8 inches
high. The lower case "o" is 7/8 inch high. The frog measures 6
inches long, 2 inches high, and 1/8 inch deep. Example of
an unmarked frog shown below indicates that not all bricks were marked.
Occasional clasts are visible on the surface composed of subrounded
granitic rock or pink feldspar, up to 3/4 inch across,
and black iron oxide spots up to 1/8 inch across. The interior
clay body is the same color as the surface and is porous
(10 percent) and contains about 5 percent clasts. This brick
was made using the sand-molded, soft-mud process.
Length 8 1/4, width 3 7/8 wide, height 2 3/8 inches.
View of the marked face of a red Union brick.
Photo courtesy of Ron Anjard
View of the marked face of an orange Union brick in La Jolla.
View of the side of the Union brick.
View of the unmarked frog of the Union brick. Donated by George L. Kennedy.
View of the side of the unmarked Union brick.
View of the rough top face of the unmarked Union brick.
Federal Census Records, 1910.
Copyright © 2007 Dan Mosier
Kennedy, George L., personal communication and brick donor, 2014.
San Diego City Directories 1910-1966.
Tucker, W.B., San Diego County, Mining in California.
California Mining Bureau Report, v. 20, no. 4, p. 368-374.
Tucker, W.B., San Diego County, Mining in California.
California Mining Bureau Report, v. 21, no. 3, p. 325-382.
Tucker, W.B., and Reed, C.H., Mineral Resources of San
Diego County, California Journal of Mines and Geology,
v. 35, no. 1, p. 8-55.
Weber, F. Harold, Jr., Geology and Mineral Resources of
San Diego County, California, California Division of
Mines and Geology County Report 3, 1963, p. 61-68.