Cob, soil test, what composition is this?

I have a plot with very "muddy" soil and had been thinking of building a little cob house on it. I did a soil shake test and found some surprising (to me) results (see attachment). I was expecting to see the soil very clay-heavy (so that I'd have to source sand from somewhere else). It's sticky when wet and very hard when dry. So I initially thought/assumed that the bottom layer was clay and the second one was silt. However after thinking about it I realized that it has to be the other way around (sand being the heaviest, then silt, then clay). But now I'm confused. It seems that it would have to one of the following three compositions:

1. Silt, clay, water
2. Sand, clay, water
3. Sand, silt, water

Due to the fact that exposed soil on the plot gets muddy/slippery when wet I wouldn't have thought that there'd be much sand at all in the soil (and thus I'd guess that it's #1). Is that a wrong assumption? How do I figure out which composition it actually is?

PS. The top layer of the sample to the right looks a bit wonky/uneven as the soil parts were so hard (had dried in the sun for a couple of days after I dug them up from ~1 meters depth) that there were still some hard clumps when/after shaking.

I need a better photo of the grain sizes.
How long did it take to settle the way it has?