Erath Co is in the northwest part of the Lampasas Cut Plain karst region. It would be waaayyyyy cool to have that area geologically surveyed to see if the depression is indicative of a larger underground feature (i.e. cavern). Might give a local univeristy a call. Geologists love new field lab opportunities. Would be an easy, free way to determine if the area might be prone to a future sinkhole. Maybe even figure out a way to include a HS science class field trip. Give the kids a chance to lern em up sumpin.
Yup. The well was about 50 feet from the maybe 20x10 foot oval depression on the side of a ridge maybe 20 feet below the ridgeline. The well collapsed in the last 5-6 years about 10-12 feet down, but I remember it having water in it during some of the driest times. Right now the depression is pretty well choked with mesquite and grapevine, so I'd imagine even once the trees are cut, those mesquite taproots will complicate any sort of digging, but I think one of the cousins may have a core sample drilling rig (picked up at auction, and used to make a few 4" irrigation wells to the Paluxy aquifer for neighbors before disappearing into the giant barn o' crap we don't need right now) that would be educational to take up there and do some samples down to 40' or so.
Bedrock depth along that part of the ridge seems to range from exposed crumbling limestone (gravel up to maybe 2 cubic foot blocks, though it's hard to say since larger blocks would have been carried off as building material a century ago) to much larger solid slabs about 8-10' down. Farther down the ridge it runs more to high iron sandstone and some petrified wood, still of varying depth as parts have been washed out up to 8' deep and other parts moved around making farming fields, orchards, stock tanks and irrigation ditches, so it's hard to estimate where the natural ground level would have been. If I could figure out what the depth is right there, and it's shallower than 6', even driving a rock bar down to it in a tight grid pattern could be educational to map out any fissures big enough for the bar to run into.
As it stands, it's a good 200 feet from anywhere we've even thought about building anything since the original workers' cabins that were dismantled right after the Depression ended, and nearly a quarter mile from any current buildings except one neighbor's doublewide maybe 350 feet on the other side of the ridgeline. Frankly, if there is a semi-dry cavern down there, I'd want to open it up if for no other reason than to have some truly tornado proof storage/shelter.
Be careful they don't get lost in the sinkhole though. Or find a closed up aquifer full of dangerous man eating beasts.
I've always wondered what saber tooth tiger tastes like. Bet I could charge millions for the hunt.
