The Ventura Basin (see index map, fig. 1) has long been one of the important oil-producing districts of California. The eastern part of the Basin includes some of the oldest oil fields in the state and also several of those most recently discovered. Since 1937 several new fields have been discovered in the area and doubtless more oil remains to be found.
The first work of the U. S. Geological Survey in this region was reported by G. H. Eldridge and Ralph Arnold in Bulletin 309 (1907). The Survey's Bulletin 753 by W. S. W. Kew (1924) described part of the region studied by Eldridge and Arnold as well as much of the remainder of the Ventura Basin. Since the publication of Kew's report, and especially since 1937 when the Newhall-Potrero oil field was discovered, interest in the eastern part of the Ventura Basin has steadily increased.
The present report covers a small part of Kew's area on the larger scale of 1:12,000 (see index map, fig. 1). Attention is focused on the outcrop geology, particularly the stratigraphy. Subsurface data were collected where available, but they are incomplete.
