This [approximately] 1.5’ x 3’ document is hand-drawn and scribed to show the Islais Creek properties acquired by the Spring Valley Water Works (SVWW), not yet Company, in 1863. The map also shows the 10 foot-wide “Right of Way” established for SVWW flumes. Very thorough surveyor notations are included in brown, almost reddish, ink. A few penciled annotations depict street names imposed upon the original document.

“Rincon de las Salinas” translated into English is “corner of a salty marsh.” This was the area around Islais Creek Estuary. The name of the creek is derived from a Salinan (Native American) word “slay” or “islay,” which is the name for the Prunus ilicifolia, wild cherries which grew in the area.

The historic Islais Creek, the largest body of water in the city covering an area of nearly 5,000 acres, had two main branches. One originated near the southern slope of Twin Peaks, and the other began at the present-day intersection of Cayuga Avenue and Regent Street. Together it flowed generally eastward and flowed out into the Islais Creek Estuary.

The Rancho Rincon de las Salinas y Potrero Viejo grant consisted, in fact, of two grants – Rincon de las Salinas (granted in 1834), around Islais Creek, and Potrero Viejo – or “old pasture” – (granted in 1839), part of Mission Dolores. The properties were granted to Jose Cornelio Bernal.

Following the Mexican-American War when California was ceded to the U.S., the Treaty of Guadalupe Hidalgo provided that the land grants would be honored. So, a claim for the ranch was filed and the grant was transferred to Jose Cornelio Bernal’s wife and son (Jose Cornelio Bernal having passed) in 1857.

The family gradually sold off the land. In the 1860s the rancho was subdivided into small lots, primarily but not exclusively populated by immigrants who farmed the land and ran dairy ranches. And SVWW ponied up for their share of the action.

Per Wikipedia: “Right of way” is the legal right, established by usage or grant, to pass along a specific route through grounds or property belonging to another”, or “a path or thoroughfare subject to such a right”.

Per Wikipedia: A “flume” is a human-made channel for water in the form of an open declined gravity chute whose walls are raised above the surrounding terrain, in contrast to a trench or ditch.

The chain is a unit of length equal to 66 feet (22 yards). It is subdivided into 100 links or 4 rods. There are 10 chains in a furlong, and 80 chains in one statute mile. The use of the chain was mandatory in laying out US townships. A federal law was passed in 1785 (the Public Land Survey Ordinance) that all official government surveys must be done with a Gunter’s (surveyor’s) chain. Distances on township plat maps (a map, drawn to scale, showing the divisions of a piece of land) made by the US General Land Office are shown in chains.