The Calaveras Co. death, birth,marriage etc indexes do not have any Penberthy names listed. There was a probate for a James D. Schmadeke so I took a look at that file and he was Rebecca Estella's husband. He died 8/7/9104 in Tuscon Springs and was listed as a resident of Calaveras Co. His wife Rebecca Estalla, age 20, filed to be administator of his estate and she filed from SF. She was age 20 at the time. He left $580 cash, and unknown value stock in the Libra Mining Co, North Star Mining Co, Blair Consolidated Mining Co. She named a son of her husband, James D. Schmadeke age 8 and a daughter of her and her husband Hazel age 3.
No other info that would help you I'm sorry to say.