To date, the collection consists of about 4,200 unprocessed, surficial sediment (grab) samples collected by Maryland Geological Survey (MGS) from the bottom of the Maryland Chesapeake Bay and its major subestuaries between 1976-1984, as part of the Chesapeake Bay Earth Science Study (CBESS), a multidisciplinary research effort authorized by Maryland and Virginia through the U.S. Environmental Protection Agency (EPA). MGS collected samples according to two sampling schemes, mid-bay and nearshore, and then processed them to develop a baseline inventory of certain physical and geochemical characteristics of bay bottom sediments, in particular, water content, grain size composition, and carbon and sulfur content. Since collection, samples have been stored indoors, but at ambient outdoor temperatures. In the future, other bottom sediment samples from the same area may be added to this collection.