Mark Dean was the only one to respond with, “Here’s a cool history from “Rock Climbs of Tahquitz and Suicide Rocks,” by Randy Vogel, 1985 ...”
“More recently, Tahquitz Rock drew the attention of turn of the century hikers who often worked their way to its class 2 summit. During this period of time Tahquitz was also referred to as ‘Lilly Rock’ and ‘The Pallisades.’ To this day, Tahquitz is often mistekenly refered [sic] to as Lilly Rock.”
However, according to www.summitpost.org; “Named Lily Rock in 1898 by a USGS team; it has been thought that this was possibly for its lily-white appearance. But T.W. Patterson of Riverside has seen an old photograph of Lily Eastman, on the reverse of which is written ‘She was the one for whom Lily Rock was named’.
“Lily was the daughter of Dr. Sanford Eastman, the first Secretary and a Director of the ‘Southern California Colony Association’ which later became Riverside. She was much admired locally for her grace and beauty.
“She and her father, both suffering from tuberculosis had come to Riverside for their health, but she nonetheless died young and was mourned by many. How the USGS could have become aware of her is unknown.
“It had previously been known as ‘Taukwitch Rock’ (by area pioneers) and allowing for many variants in spelling, ‘Tauquitz’ [sic] is still its preferred name by rock climbers.”