The area described in this report comprises 712 square miles centered on the City of Austin. The area extends north almost to Round Rock, south to the vicinity of Buda, east to just beyond Manor, and west to about 5 miles west of Oak Hill.

This Guidebook represents an updating of Bureau of Economic Geology Guidebook No. 5, Field Excursion-Geology of Llano Region and Austin Area. It also represents a modification of Geology of the Llano Region and Austin Area, Texas, published by the Shreveport Geological Society in 1971.

Endemic ammonite faunas evolved from cosmopolitan faunas in a series of successive episodes over about 35 million years of the Cretaceous of the Gulf Coast of the United States.

This history of geology at The University of Texas was prepared for the dedication of the new Geology Building, November 1967. It is a brief history; many details have been omitted. The names of most graduates and some faculty will not be found.

Since the days of R. T. Hill (1901) two Upper Cretaceous lithic units have been used as formations but have remained unnamed.

This paper brings part of the classification of upper Albian ammonites up to date and up to modern standards for some of the Texas species. Twelve new species are described (Drakeoceras georgetownense, D. drakei, D. arringtoni, D.kummeli, D. gabrielense, D. dellense, D.