http://pubs.usgs.gov/sim/3062/needles_readme.txt - this 
file

Description of digital dataset files posted on this 
website:

needles_meta.txt - FGDC compliant metadata. This metadata 
report provides an overview of the data contained in this 
geodatabase. In addition, each feature class (except 
annotation) has its own metadata report which should be 
referred to for Spatial Data Organization, Data Quality, 
and Entity and Attribute information.

needles_db.zip - zipped package of files necessary to 
  create an ArcMap Personal Geodatabase project.
    -- readme_needles_db.txt
    -- Needles24.mdb - Personal Geodatabase
    -- needles.style - ArcMap style for symbolizing data
    -- needles_base.zip - zipped 1:24,000-scale DRG base

needles_shape.zip - zipped package of Feature Classes 
  converted to shapefiles to facilitate use of the data in 
  ArcMap and other applications.
    -- readme_needles_shape.txt
    -- needles24k.style - ArcMap style for symbolizing data
    -- needles_base.zip - zipped 1:24,000-scale DRG base
    -- Shapefiles include:
      -- needles_auger_holes.shp - auger hole locations
      -- needles_gpt.shp - paleosol and tephra geologic 
           points
      -- needles_scarp.shp - erosional scarps
      -- needlesatd.shp - attitudes
      -- needlesglg_arc.shp - geologic contacts
      -- needlesglg_poly.shp - geologic unit polygons
      -- needlesglg_pt.shp - geologic unit labels