But the evidence unearthed by the Fernbank archaeologist and his team of scientists, students and volunteers began to mount with each dig.
"What we have now is the best-documented collection of Spanish artifacts in Georgia," Blanton said. "Many are unique, and they are the only examples of certain artifacts ever found outside Florida."
The most significant finds at the remote, privately owned site near the Ocmulgee River, believed to have been occupied by a Native American community from the end of the 15th century through the first decades of the 16th century, include nine glass beads. Among them are chevron ones believed to be "calling cards" of de Soto due to their distinct patterns and limited production. The soil has also surrendered six metal objects, including three iron tools and a silver pendant.
Native Americans did not have glass or metal before the arrival of Europeans.
"A site like this is a treasure to Georgia, to the region and maybe even a treasure to the nation," Blanton said during an interview from Mobile. "The most plausible explanation is that this is a de Soto site, not just a site with de Soto things but very likely a site that de Soto was on. And that's just rare, rare, rare, and I have to admit very exciting."
Yet it took several years for the archaeologist -- initially drawn to the site in search of the early 1600s lost Spanish mission settlement of Santa Isabel de Utinahica -- to be persuaded.
He recalls that a volunteer early on innocently asked whether Blanton thought they'd find evidence of de Soto. "And my reaction really was just to laugh and say, ‘Of course not.' " A couple of weeks later, when a Cobb County high school volunteer summoned the archaeologist over to her sifting screen and showed him the first glass bead discovered at the site, he merely considered it a beautiful "head-scratcher."
Despite finding more beads in summer and fall 2007 digs, Blanton, "still committed to the mission story," had his crew excavating different areas of the Telfair site in the summer of 2008. "But I couldn't stand it, so this summer, we went back in a big way to the place producing the earlier artifacts. It was too important to turn your back on."
And that rich area, where an Indian council house is believed to have once stood, produced more and important pieces, including a new Spanish bead, a Nueva Cadiz. It's an indicator of pre-1550 activity and utterly uncommon in terms of Southeastern finds.
"I literally let out a whoop that probably could have been heard in Atlanta," Blanton said of this ah-ha moment, "and jumped as high as LeBron James."
Finally convinced, Blanton returned to Atlanta at summer's end, further researched the artifacts and began preparing last week's presentation before the tough jury of more than 100 peers at the archaeological conference.
"The reaction was very positive for the most part," Blanton said. "There are still some holdouts, still some debate, but that will always be the case. On the whole it's been gratifying to know that I think we've persuaded probably the majority."
One who is persuaded is state archaeologist David Crass.
"I have a high degree of confidence that what David has posited is in fact the case," Crass said. "The normal course for an announcement of this sort is that there will be a period of back-and-forth between scholars that will play out in conferences and professional journals until in that contest of ideas, one is accepted by the archaeological community. I would put my money on Fernbank being correct."
His first presentation made, Blanton now has another writing assignment: grant proposals so he can return next summer to Telfair and keep digging.