For all the faults attributed to the San Andreas, its one very soothing aspect has been an enormous spiderweb of cracks spreading throughout the geologic formations of what became Riverside County. These fissures yielded springs and grottos of warm waters to which thankful pioneers and snake-oil salesmen alike attributed curative powers. In the 20th century, vacationers seeking relaxation, together with those afflicted with a myriad of maladies, came...