Dear Matmail: The highest man-made point in the county [mentioned in an answer several weeks ago] is at the top of Hot Springs Mountain, but it is the creaky, abandoned fire tower, not the radio tower pad. Anyway, if you’re not too mad at me for correcting you, I have a question of my own.

On the beach below Torrey Pines State Park is a rock called Bathtub Rock (also known by other names). On the top of the rock is a nearly perfect square hole about six feet across. I had a friend who said he and some friends excavated the sand from the hole in the 1930s. He said they used ladders and buckets until they were about 20 feet down, but the straight sides just kept on going. Do you know who dug the hole, how, when, and why? — Dave Moser, Olivenhain

Don’t know the guys personally, but I think I’ve got your answer anyway. (But by all means, correct me if I’m wrong.) With a lead from the Torrey Pines park rangers, I grabbed pick and shovel and headed for the gold mine that is the research archives of the San Diego Historical Society. And eeuuu-doggone-reeka, there it was in an interview with Miss Alice Rainford, published in a 1964 edition of the La Jolla Journal.

One day in 1894, Alice recalled, she and her mom met San Diego County Constable John Bloodworth. They mentioned to him that they’d seen evidence of a vein of coal at the beach, near the slab of sandstone then called Table Rock. Based on the Rainfords’ tip, John and his brother did a little prospecting. The hole in the rock is the entrance to the Bloodworths’ exploratory coal mineshaft. As Alice remembered, the men dug it with crowbars and sledgehammers. At some point the brothers abandoned their quest, and no coal was ever taken out of Table Rock.

Coal at the beach isn’t such a looney idea. In various spots along the coast, you can find thin, crumbly coal veins in cliffs. The so-called Mormon Mine on Point Loma promised to yield abundant, high-quality anthracite in the 1850s. Local papers of the day even dreamed of San Diego as a glorious “Pittsburgh of the West.” Lucky for us, the mine filled with seawater and the Mormon miners returned to Utah, putting a halt to that potential nightmare. Mount Soledad and Rose Canyon also had failed coal mines during the same era.

Table Rock is renamed Flat Rock on most maps, but it’s also known as Bathtub Rock or the Indian Bathtub. Alice had a story for that too. She said the rock was named Indian Bathtub during the Depression by an imaginative man from a WPA encampment on the hills above the beach. And Matthew Alice has a story for that one. The WPA was a Depression-era federal program that gave shovels and hammers and paintbrushes to hordes of unemployed Americans and put them to work on public projects. “WPA” stood for “Work Projects Administration.” But Roosevelt’s detractors perused the men on the job and renamed it “Whistle, Pee, and Argue.” Miss Rainford was just too polite to mention that bit.