I found this on Monday:
BIG ESTATE FOR A KANSAN
The Death of Thomas Moreen In Wyoming
Left His Family 19 Years Ago
Salina, Kas., July 24 -- Philip Moreen of this county has just learned of his father's death in Wyoming and that he and his sister, Mrs. T. Carroll of Denver, are the only heirs to a large fortune left by the parent. Thomas Moreen was formerly a resident of this county and left his family nineteen years ago. Fourteen years ago he was heard from indirectly for the last time. Mrs. Carroll in reading a paper last week read the obituary of Thomas Moreen and immediate correspondence developed the fact that he was her father. The fortune was made in mining and the cattle business. Philip Moreen and his sister will go to Wyoming early next week to claim their estate.
Kansas City Star, July 24, 1907, page 5
- Thomas isn't indexed in the 1900 census in Wyoming, at least under the name Thomas Moreen
- Wyoming didn't start requiring death recording at the state level until 1908
- The Wyoming newspaper project hasn't gotten very far on digitizing newspapers for the time period I'm interested in and I'm not finding a Denver paper for the time, either.
- Ancestry.com's collection of digitized Salina papers doesn't yet have 1907.
- He doesn't show up in the BLM land patent database
- I found a brand book for Wyoming, but it starts after a 1909 law and was published in 1913. State registration of brands started in 1909; before that they were registered at the county level, and all I know is the state.
- I need to email the Wyoming Stock Growers Association. According to Wikipedia, they were well established by the early 1900s and kept brand and member info; some of their records have been moved to the University of Wyoming, so I'll need to contact them, too.