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It's more likely than you think
It looks like you're the other side of the extreme we're on. Our yard has about 3" of top soil followed by literally solid clay. It's impressive how uniform and uncontaminated it is. I don't know that I hate it, but I often wonder if I would prefer a sandy yard instead.
This particular bed used to be flowers and other ornamentals from the previous owners, so there's a nice mix of stuff in it. On the other side of my driveway where I dug my squash arch, it was like pulling minecraft blocks out of the ground: solid clay with a few inches of topsoil. All my other beds are raised, I just decided to try some new stuff this year