I am using the 'stable' debian packages, as referred to at
http://lcg-heppkg.web.cern.ch/lcg-heppkg/debian/install.html

The geant4 package depends on libgean4-dev, which in turn depends on clhep2-dev (version >= 2.0.4.7), but the latest version of clhep2-dev available in the repository is version 2.0.4.6-1.1 .


Steps to reproduce on Kubuntu 10.10 'Maverick':

Add the following lines to /etc/apt/sources.list:
deb http://lcg-heppkg.web.cern.ch/lcg-heppkg/debian stable hep
deb-src http://lcg-heppkg.web.cern.ch/lcg-heppkg/debian stable hep

Enter the following commands as root:
apt-get update
apt-get install geant4

You will get the following output:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 geant4 : Depends: libgeant4-dev but it is not going to be installed
          Depends: libgeant4-plists-dev but it is not going to be installed
          Depends: libg4opengl-dev but it is not going to be installed
          Depends: geant4-examples but it is not going to be installed
E: Broken packages


A little investigation determines that the unfulfilled  dependencies all trace back to the old versions of clhep2 or clhep2-dev.