Vintage Pottery Bowl

Measures 14" in length, 10" in width and 3 1/2" in height and weighs 6 pounds. I have no idea of the manufacturer. When I bought the bowl, I had wondered if it had been meant to be used as a dough bowl, but they are usually a perfect oval. I've kept it on my kitchen table with fruit off and on for many years. I am not an informed collector and have never looked for a particular maker, but rather would see something I loved, or liked the way it felt and would buy. Until I washed the bowl today to list, I had never noticed what might possibly be a manufacturing mark. It could be a "W" or "M" but have no idea what it could mean or it might just be a manufacturing flaw that looks like a letter. Please look at the photos and decide for yourself. There are no chips, cracks or breaks, but lots of what looks like manufacturing flaws gone bad. Please check all the photos carefully because the bowl is far from perfect. I will provide additional photos or answer any question regarding this bowl. I need the zip code to calculate the postage.