ESTUDIO PALINOLOGICO DE LA CUENCA ISCHIGUALASTO - VILLA UNION, (TRIASICO), PROVINCIAS DE SAN JUAN - LA RIO]A l. INTRODUCCION. II. MONOAPERTURADOS

Abstract

A brief stratigraphical description of the most complete sequence of Triassic sediments found to the east of the Basin, at Agua Escondida, is given. lt consists of the four following formations: F. Ischichua, F. Los Rastros, F. Ischigualasto and F. Los Colorados (see figs. 1-2), which according to the their vertebrate faunas, range from lower Middle to Upper Triassic. Some remarks upon the stratigraphic nomenclature, as used by other authors, are made and then revised. The second part of the paper contains descriptions of the most important and abundant monoaperturates; these are 16 different "forrns" distributed in 11 species of 5 genera (.3 new species, 4 new "formae" and several new combinations are presented). Discussion is made of several new genera established by Jain (1968). No conclusions are drawn, but a table is given which shows percentage distribution of the "forms" described along the Los Rastros Formation (from a series of selected sarnples).