Today, my mother asked me to come see something in their Los Gatos back yard. She took me out to the corner of their large lot (large for Los Gatos, anyway), and she pointed out to me some black, shiny substance seeping out of the ground in patches, and along a line about 10 feet in length. The last heavy rain had made this substance come to the surface. I said "It looks like oil," and she said she thought so, too. I stuck my finger in it, and it was black, slick, and after I'd rubbed it around to...