http://pubs.usgs.gov/sim/2007/2977/cmreadme.txt

Description of digital dataset files posted on this website:

cmreadme.txt - this file

cmmeta.txt - FGDC compliant metadata. Each Geodatabase Feature Class also has its own metadata.

cm_db.zip - zipped package of files necessary to create an ArcMap Personal Geodatabase project.
    -- readme_cmdb.txt
    -- cameron100k_mdb.zip - zipped Personal Geodatabase
    -- cameron100k.style - ArcMap style for symbolizing data
    -- cm_base.zip - zipped 1:100,000-scale DRG base

cm_shape.zip - zipped package of Feature Classes converted to shapefiles to facilitate use of the data in ArcMap and other applications.
    -- readme_cmshape.txt
    -- cm_shapefiles.zip - zipped shapefiles
    -- cameron100k.style - ArcMap style for symbolizing data
    -- cm_base.zip - zipped 1:100,000-scale DRG base