http://pubs.usgs.gov/imap/i2766/mtrreadme.txt

Description of digital dataset files posted on this website:

mtrreadme.txt - this file

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

mtr_db.zip - Zipped package of files necessary to create an ArcMap Personal Geodatabase project.  Includes:
-- readme_mtrdb.txt
-- mtr100k.mdb - Personal Geodatabase
-- mounttrumbull.style - ArcMap style for symbolizing data
-- f36113a1.tif - 1:100,000-scale DRG base
-- mtr.lyr - ArcMap layer file with symbolized feature classes. When opening this file in ArcMap data source links will be broken and projection will be undefined. Setting data source for base (f36113a1.tif) and one feature class will restore all other data source links. Set projection to NAD_1927_UTM_Zone_12N.

mtr_shape.zip - The authors have converted feature classes to shapefiles and created a style file to facilitate use of the data in ArcMap and other applications. mtr_shape.zip includes:
-- readme_mtrshape.txt
-- mtr_shapefiles.zip
-- mounttrumbull.style - ArcMap style for symbolizing data
-- f36113a1.tif - 1:100,000-scale DRG base