ftp://ftp.remotesensing.org/geotiff/samples/usgs/README
About these files:

These are USGS Image digital elevation model datasets,
reprocessed by SPOT and stored in GeoTIFF georeferenced 
format. A valid GeoTIFF 1.0 reader should be able to 
handle any of these files (assuming they can handle 
16-bit pixels), without any further metadata. 

The ".txt" files give a metadata dump of the 
corresponding. ".tif" datasets.  The only difference between 
the "m" files and the "i" files is byte-order, which 
valid TIFF readers should be able to handle on the fly. 

The 16-bit GeoTIFF files are made by Dr. Niles Ritter of 
NASA-JPL (Jet Propulsion Laboratory) from inputs provided 
by SPOT Image Corporation.  These files are available for
public examination, demonstration, or other support
of the GeoTIFF format.  

Please send comments regarding these files to the
GeoTIFF email routing:

mailto: geotiff-list@tazboy.JPL.NASA.GOV 

Comments not for broad distibution may be sent to:

ruth@spot.com

More info about GeoTIFF can be found from the 
NASA/JPL GeoTIFF Home Page:

http://www-mipl.jpl.nasa.gov/cartlab/geotiff/geotiff.html

The GeoTIFF page and others are pointed to from the SPOT GeoTIFF page:

http://www.spot.com/anglaise/news/press/devconf/resource.htm

... and FAQ:

http://www.spot.com/anglaise/news/press/devconf/gtiffaq.htm

Thanks for your interest in GeoTIFF format.  

... Mike Ruth
SPOT Image Corp