I said "suspect" rather than "suppose", which may be a useful clue: It just happens to look that way to me. I have no particular reason to trust my judgement on

I said "suspect" rather than "suppose", which may be a useful clue: It just happens to look that way to me. I have no particular reason to trust my judgement on this. I'm sure it isn't much deeper than 1ft, in any case. (Nor much shallower, for that matter.)