The Radiolaria described in this paper came from tw o areas in southern California, the Palos Verdes Hills and the Newport area. M ost of these deposits consist of or ganic shales referred to as the M onterey shale. In the Palos Verdes Hills the deposits are about 2500 feet thick and have been divided into five lithologic members. Three are named (beginning at the base) the Altam ira shale, the Valmonte diatom ite, and the M alaga mudstone. Radiolaria were abundant in the latter two members. M ost of the Newport area samples studied contain a very large proportion of species com m on to the Valmonte member of the Palos Verdes Hills. The writers conclude that the shales containing the Radiolaria of the Palos Verdes Hills and New port area were laid down under conditions not greatly dissimilar to those existing in the adjacent Catalina Channel under open sea conditions; and that at least the upper portion of the M alaga mudstone is almost certainly bathyal, although possibly other portions were deposited under shallower water conditions. N inety-one species, all of them new, are herein described.
INTRODUCTION AND ACKNOWLEDGMENTSSeveral years ago the writers' attention was called to the occurrence of Radiolaria at a number of Miocene localities in southern California. Woodring, Bramlette, and Kleinpell (1936), in describing the geology of the Palos Verdes Hills, noted that radiolarians were abundant in a number of their localities. The writers, through the courtesy of the late Dr. R. D . Reed, at that time chief geologist of the Texas Oil Company, obtained samples of the shales from the localities referred to in that paper, as well as a considerable number of other samples, including several from the Newport Bay area, a few miles to the southeast. Most of these samples yielded well-preserved radiolarians, described in this paper, the first from the marine Miocene of Western North America.ABSTRACT 2 MIOCENE RADIOLARIAN FAUNAS FROM SOUTHERN CALIFORNIA " The M onterey shale has an estimated thickness of 2500 feet in the Palos Verdes Hills, and the base is not exposed in the region where the oldest rocks crop out (Fig. 2). The form ation consists of five main lithologic units, consisting, in ascending order, principally of silty shale, porcelaneous and cherty shale, phosphatic shale, diatom ite and radiolarian mudstone. Other kinds of rock are found in each unit; those mentioned are the prevailing ones. Perhaps each of these divisions deserves member rank, but in view of the absence of adequate exposures the three lower ones are grouped as the Altam ira shale member. The diatom ite constitutes the Valmonte diatom ite member; and the radiolarian mudstone is called the M alaga mudstone m em ber."All samples from the Palos Yerdes Hills containing radiolarians described in this paper came from the Valmonte diatomite member and the Malaga mudstone member.
The Valmonte diatomite overlying the Altamira shale consists of dia tomite and diatomaceous silt or clay shale, estimated as 750 feet thick. Six samples came from this mem...
