Shenango Pottery Bowl

Q: I ate my cereal out of this bowl every day from the time I was about 5 years old. I’m 78 years old now and still use the bowl occasionally. It’s like an old friend. The bowl and I are both in great shape–strong, sturdy, and resilient. In the not-too-distant future, I want to give the bowl to my grandson with the hope it will survive future generations. But it needs a little more history attached other than that it was Grandpa’s cereal bowl. I would appreciate any information you can give me. The bowl is 9 1/4 inches wide and has this mark on the bottom.