1. Bedrock geologic map of the Seattle 30ʹ by 60ʹ quadrangle, Washington [microform] Yale Public content 1991. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; Books and Open-File Reports Section, distributor. English. Public. Washington (State) and Seattle Region.