It's garter stitch stripes (lovely and squishy) for most of the body with colorwork arrows around the bottom edge. The green is Stephen West's exclusive colorway. The white/black is apparently exclusive to the yarn company hosting the shawl club, but not exclusive to the club members. The green is called Moss Gatherer, the black/white is Newsprint. Both are Lorna's Laces Shepherd Sock 80% wool, 20% nylon.
I was seriously just thinking that I needed to add a little garter stitch to my WIPs for knitting at home after long school days. This will be perfect. Best gift ever!