Dry stacked rock walls from the historical era are commonplace in the Yuba watershed. They were used as retaining walls on pack trails, wagon roads, ditches and railroad grades. Rock was also stacked to build foundations, cellars, dams, bridge abutments, races, sluices, walls, buildings, wells, culverts, fences, pens, chimneys, hearths and to create terraces for work, living and agricultural purposes. Most walls were purely functional while others display serious craftsmanship. There is no lack of rock in the Sierra Nevada. The locations of boulders, field stones, exfoliating slopes, and concentrations of exposed rock were well known, but as a general rule projects were constructed with materials at hand. A thorough look at the rich topic of rock work is beyond the scope of this humble post so I'll limit this commentary to some examples of dry stacked rock walls.
Tyler-Foote Crossing Road / Middle Yuba
TRAILS and ROADS
Trails or roads often required retaining or flanking walls on slopes to hold back erosion that could cover the tread from above or erode it from below. For major projects like roads or ditches a crew was hired or assembled. Generally, anyone with a strong back could find work. The Chinese often formed labor crews, especially after 1869 when the railroad was completed, but they were by no means the only nationality that built rock walls. For instance, the impressive rock retaining walls on the road to Foote's Crossing of the Middle Yuba was built by crews of Italians and Slavs.
Bridgeport/ South Yuba
PASTURE WALLS
Most of these walls are found on foothill ranches with meadowland and nearby water. Also called "tossed walls", they are common in Penn Valley, Spring Valley and the Spenceville Wildlife and Recreation Area as well as many other places. H. F French wrote a letter to The New England Farmer in October of 1855. In it he said, "A stone wall is doubtless the cheapest and most durable of all fences, and where stones are constantly working up in your fields and must be removed, no doubt this is the best use to make of them", ... "our fields are cleared, and the boys have picked stones for a hundred years." Naturally some of the walls followed recorded property lines. This practice became commonplace when California became a State and surveying became more precise and important than it was in Alta California.
Stacked Rock Retaining Wall in Downieville/ North Yuba
Stacked Rock Retaining Wall in Nevada City/ Deer Creek
TERRACING
In the mountains, where there is little flat ground, it was essential to create terraces for buildings and machinery and to manage agricultural plots. The gold rush brought Italians from Genoa, who came from the region of Liguria where there was a long tradition of stacked rock work and an estimated 25,000 miles of terraced hillsides. They built many of the rock walls and terraces in the North Yuba Canyon near Downieville and Sierra City, among other places.
Stacked Rock Wall made with Quarried Rock/ Nevada City
Plug and Feather Method for Splitting Stone
Quarrying a Bedrock Mortar Outcrop/ Sweetland/ Middle Yuba
This is disrespectful to the indigenous Nisenan who were the original stone workers here.
GRANITE BLOCKS/QUARRYING
Men from New England and the middle Atlantic states brought their own tradition of rockwork to the Yuba River region. They had been quarrying and building with stone since the 17th century creating rectangular blocks of granite from rock outcroppings they called "surface ledges." They used an ingenious but simple system for splitting rock in a straight line.
The plug and feather method to hew blocks of stone first appeared in late 18th century on the east coast and by the latter 19th century was widely used in the west. The process involves drilling holes in a line, typically six or seven inches apart, then inserting feathers, which are half-round thin metal shims, while the plug, a metal wedge, is placed between the feathers and then hammered causing the rock to split along a straight line. You can still buy plug and feather tools.
Bowman Dam on Canyon Creek/ South Yuba (1889)
Constructing a Crib Dam
IMPOUNDMENT WALLS
Historically dams and reservoirs both captured and diverted water. Beginning in 1850 there has been of an emphasis on water management in the north-central Sierra Nevada. This is still the case today. Large quantities of water were originally used for hydraulic mining, followed by hydroelectricity development and irrigation. Almost all of the "lakes" in the Yuba-Bear watersheds are dammed and are actually reservoirs.
Stacked Rock Sluice/ South Yuba
Remnants of a Blacksmith's Shop in a Hydraulic Mine/ South Yuba
MINE ROCK
Underground gold mining produced angular waste rock and gangue, while placer mining (including hydraulic) created rounded tailings, ranging in size from gravel to boulders. These materials were useful for on-site construction projects and the constant road work that accompanies mining ventures.
A Stacked Rock Narrow Gauge Railroad Grade/ South Yuba
A Corner of the Foundation for the North San Juan Methodist Church
Many of the walls take on a beautiful patina as they age, especially in the winter and early spring when the moss and algae pulsate in shades of vivid green, orange and yellow. There is a symbiotic relationship that can develop between moss and man when the walls provide habitat for moss which, in turn, strengthens the wall's stability by binding the individual rocks together. It would be an unusual event to not see a dry stacked wall while out hiking in Yuba River country.
