The following work is part of a long term study of sediment trans port on the Continental Shelf of Central California. In particular, it is hoped that the data presented here will be useful also to the general study of the factors that influence the natural environment of Bolinas Lagoon now being conducted as a cooperative effort involving the University of California, Berkeley; the U. S. Corps of Engineers; the U.S. Geological Survey; the Department of Agriculture, Soil Conservation Service; and consultants for the Bolinas Harbor District.

The analyses of the marine sediments of Bolinas Bay were done at the University of California, Berkeley, utilizing the facilities of the Departments of Civil Engineering and Geology and the Institute of Marine Resources. The results of the marine study will be presented in three separate volumes:

Part A — Introduction and Grain Size Data Part B — Mineralogical Data Part C — Interpretation and Summary of Results

This section of the study of Bolinas Bay deals with the heavy mineralogy of the 0.175 - 0.124; 0.124 - 0.088; and 0.088 - 0.061 mm size fractions of 49 sediment samples (Fig. 1) [see Isselhardt and others (1968) for grain size and sizing procedure] plus the 0.124 - 0.088 and 0.088 - 0.061 mm size fractions of one disaggregated cliff sample 2030. Offshore rock samples 1974, 1975, 1976, 1977, 1998 and 2000 and cliff and shore samples 2027, 2028, 2029, 2031, and 2032 were not dis aggregated for mineralogical analyses. These rock samples will be discussed in Part C. Sample 1988 was lost and 2007 was too small for analysis.

The treated size fractions were divided further by separation in the heavy liquid tetrabrom-ethane (Krumbein and Pettijohn, 1938, p. 325) with a density of 2.95 gms/cc. Particles with a density greater than 2.95 gms/cc were called heavy. Particles with a density equal or less than 2.95 gms/cc were designated light. Grain mounts were made of both the heavy and light particles of each size fraction on glass slides with Cadex mounting media (index of refraction = 1.55).

Grain size and heavy mineral analysis of 6 cliff, 12 beach, and 44 marine sediment and rock samples from Bolinas Bay were done as part of a study of sediment transport on the continental shelf of California.

The following work is part of a continuing study of the sediments and sedimentary processes of the continental shelf of central California done in cooperation between the University of California, Berkeley and the Coastal Engineering Research Center, U.S. Army Corps of Engineers. Sediment analyses of the samples were done at the University of California, Berkeley, utilizing the facilities of the Departments of Civil Engineering, and Geology, and the Institute of Marine Resources. The results of this study will be presented in three separate reports:

Part A Part B Part C Introduction and Grain Size Data (this volume) Mineralogical Data Interpretation and Summary of Results.

The first two reports, Parts A and B, raw data will be presented with little or no interpretation. In Part C the authors' interpretation of the data plus background information and previous work in the study area will be given.