Here in this hollow tracks have been encountered of large livestock, which some said were made by bears; others, by buffalo (elk).

As we were upon the point of setting out from the spot, three very well-behaved heathens came over from the villages here, seeking us out laden with a good share of black pies and a sort of cherries[1] that they made a present of, and they followed us along well pleased, giving us to understand we should go to their village [and] they will give us food.

(A great many madroños, small and large, have been met with during these two days' march, laden with fruits the size of so many beads off our rosaries.)"

[9][10] The Crystal Springs Hotel tract was constructed around the 1860s on leased land, located 4 mi (6.4 km) from the San Mateo train depot and along a stagecoach stop, and around this hotel a small town developed including a dairy and farms.

[12] There is speculation if any of the town structures were left prior to the dam completion, however according to a 1922 publication by the Spring Valley Water Company, "In the end, the entire 35 sq mi (91 km2) of catchment area were swept clean of all human habitation.

[14] In addition to Laguna Creek, Upper Crystal Springs Reservoir is fed by Adobe Gulch which descends from Cahill Ridge south of and parallel to Highway 92 into a wetland marsh then joins the reservoir at Adobe Point.

It also receives water from Upper Crystal Springs Reservoir via tunnels beneath Highway 92.

A considerable biodiversity of flora and fauna exist in the vicinity of the reservoir, which is located within the California Floristic Province.

Among these species are a number of rare and endangered species including Acanthomintha duttonii or San Mateo thornmint, Hesperolinon congestum (Marin Dwarf Flax) and Eriophyllum latilobum or San Mateo Woolly Sunflower.

[19] A pair of Bald eagles (Haliaeetus leucocephalus) built a nest in a Coast Douglas-fir (Pseudotsuga menziesii var.