New palynological information recovered from the middle part of the San Tel
mo Formation, upper part of the Mandiyuti Group, at the San Antonio range,
Argentinean portion of the Tarija basin, is presented. Sixty five species o
f indigenous palynomorphs were identified, together with reworked specimens
from the Upper Devonian and also Lower Carboniferous levels. The age of th
e indigenous assemblage is Late Carboniferous (approximate to Stephanian) a
nd it can be correlated with a similar assemblage, from the outcrop of the
Carapari river at the Aguarague range. The age and correlation of the Mandi
yuti Group is extensively discussed in order to reject a Early Carboniferou
s age suggested by some authors.