Rusty, sorry, I still don't really get 4 D. I can see the Car = vehicle, and I can see the R, river. I know You can be that, but 'that is'? And the 'crossing' seems superfluous, the R, river comes before the Yon. I'll keep pondering. ..
Hello, Malone!
It seems reasonably OK to me.
The word for "that" is crossing over "R" for river, giving "car R y on".
You ponder away, I am not totally convinced of my parsing!
Thanks, everyone. I was probably being too literal - taking 'crossing' as ;going over', whereas to me it looked as if the 'that' was 'following', coming after, river.
I think the earlier mention of 'yon - that is' confused me a little too (I am easily confused at times!)