At the risk of stirring things up which are best left unstirred (at least that's my sediment) take a look at this, Milum.

http://www.pavingexpert.com/gravel01.htm

What cabal?

Sifting is screening. My sifter for flour has a screen in it. And the OED says hoggin is sifted or screened gravel.

Why is it called hoggin? Because golf was already in use.

All seriousness aside, according to the OED, hoggin perhaps comes from hogging, which is the term used in parts of England for the camber of a road which keeps water from collecting on the surface, so-called because of a resemblance to the curve of a hog's back. Couple that with the fact that many of the roads were gravel, and you can see how hoggin could come to be called that.

I just hope this hasn't left you in a hoggin daze. Unless it's Rocky Road, of course.

TEd