Nearly thirty-three years ago, in September, 1913, I searched the Harlech Grits for pebbles of the Mona Complex; and the search was a success: I obtained quite enough for a decisive demonstration. Still, their numbers were not great, and to obtain them had needed persistence; the search, indeed, occupied fully a fortnight. I sought a reason at the time in the horizons from which they came, for they were not from the Cambrian base. We shall presently discern a far more cogent reason: between the Cambrian and the Complex there is more than one formation. The surprise is not in their moderate numbers, but rather that there were any at all.