The confirmation came from rock chip samples picked up within "several stacked pegmatite dykes in a north-south zone extending up to 1.7km" and named the Jailbreak lithium prospect.
Drilling is scheduled for late this month or early in November.
St George further commented "strong caesium, tantalum and rubidium values are also highly encouraging as they can be associated with significant lithium deposits at depth".
In addition, "ongoing field mapping and sampling have extended the interpreted east-west strike length of visible lithium-bearing pegmatites at Jailbreak from 400m up to 1.4km".
Jailbreak is south of Red Dirt's Mt Ida lithium play and Liontown's 156 million tonne Kathleen Valley deposit.
The previously nickel focused St George had A$4.1 million cash at the end of June.
Shares in St George were up 22.5% to 4.9c in late morning trade, capitalising the company at $34.3 million.
