The book that recorded, and in part formed, the modern legend of the San Saba treasure was J. Frank Dobie’s Coronado’s Children. It was published in 1930. Google Books has a preview of the San Saba related section, including the Broken Metate story: Coronado’s Children. Worth reading by anyone with an interest in the story.
Dobie was the premier Texas folklorist of his generation. He spent time at UT Austin as an English professor. It took more than skill as a writer to write folklore. One had to have a ready source of folklore, and Dobie was skilled at finding people who had stories to tell and were willing to tell them.
The Broken Metate story was unique in many ways, and was really the best story of all the San Saba tales. It had a great back story that reached back into the 1700’s and it stretched all the way to the present: digging was ongoing when the book went to press. It was also incredibly unique in that the location of the alleged mine was not lost. The only mystery was how exactly to find the horde of silver bars inside the old mine. That separated the legend from many other treasure tales and placed it into an exclusive group of tales where the basic treasure site is firmly established. Oak Island comes to mind. As per the tale, one knows, as per extremely unique geological features, when one is within about 50 yards of the treasure. It is those last 50 yards that bedeviled treasure hunters for more than a century.
There is a map in Dobie’s tale and the basic directions down the river and up the creek to get to the cave are correct. However, Dobie simplified the story from there. He did not really invent anything out of thin air, but he left out several important details. It is certain that he knew those details as they were in his notes. What he included and left out, and what the person who told the tale to Dobie had to say are an interesting glimpse into a folklorist who not only recorded folklore but, in the end, moved the legend along and added to it. Peoples’ lives were changed because of what Dobie wrote.
Nearly every book written about the San Saba Treasure since 1930 (in regards to The Broken Metate / Silver Creek) merely copied Dobie. C.K. Eckhardt seemed to take Dobie’s story and turn one sentence of Dobie into three sentences of Eckhardt. In the legend back-story Dobie wrote that Major Dixon went to a church in Monclova, Mexico to look for records about mines around the San Saba. Eckhardrt took that sentence, fertilized it, and and came up with Major Dixon visiting the “great cathedral” in Moncolva. Only, there was no great cathedral in Monclova in that era, none great and none small. There was no cathedral at all. And that is a clue–why would records of colonial era mines be stored at an ordinary parish church?