Wierd Agate

While at Muskallonge, a couple of people headed over from the museum to show me this wierd agate. The variety in the banding beats any agate I've ever seen. One of the other vendors thinks it is man-made. I'm not sure that I agree. Although I didn't take a picture of the top of the specimen, it appears to have matrix. Also, some of the bands are clearly translucent chalcedony, while others are macro quartz. My guess is that this is a natural specimen formed in a marine environment, probably in a sedimentary rock seam.

Have any of you ever seen a rock like this? Any ideas or opinions?