MP Mark on Pottery (not McCoy or Mountainside)

[frogpatch]

I have three pieces of pottery I found that are unfortunately in storage in another state right now. I found this discussion about the same mark as mine. The picture is identical. I researched this mark and know beyond a doubt that is not a McCoy mark and is not a Mountainside mark. Someone identified it for me years ago but I forgot what they said. I have only seem utilitarian bowls with this mark. The picture is the same mark and body as mine but mine are oval bread bowls. They are rough glazed and thick and off white or beige. The body is white clay.  Here is the link and no one on the attached forum thread was right. Mountainside has a different mark and style and McCoy never made anything like this with that mark.
I would really appreciate any help on this. I have exhausted all my resources. Odd that I have three pieces that are all similar but can find nothing.
http://www.figurines-sculpture.com/mp-pottery-mark-on-bowl.html

[mart]

Try Myra Patterson from the Van Briggle pottery !! Most of theirs were marked with the potters and or finishers initials !! Said she worked sometime in thr 70`s or 80`s !! Records of her are sketchy and the didn`t have a pic of her mark but it was just MP !!

[frogpatch]

Thanks Mart but this piece is too crude and rough for Van Briggle.