rdfs:Class vs. daml:Class ?

Please excuse another naive newby question....

In the DAML language definition, it looks like rdfs and rdf are being
used as the metamodel: daml:Class, for example, is an instance of
rdfs:Class. But if that is the case, I would expect that the Class
definitions in a DAML ontology would be instances of daml:Class.
Instead, the sample ontologies that I've seen use rdfs:Class either
exclusively or (as far as I can tell) interchangeably with daml:Class.

I understand from the Pan and Horrocks paper at
http://img.cs.man.ac.uk/jpan/Zhilin/download/Paper/Pan-Horrocks-rdfsfa-2001.pdf
that there is a layering problem in the RDF/RDF(S) definition that
prevents a clean division between successive metamodel levels. Is the
relationship between rdfs:Class and daml:Class somehow connected to
this?

I suppose all I'm really asking is: when would I use rdfs:Class and when
would I use daml:Class? And if it doesn't matter, why are there two of
them?

Thanks for your patience,

Steven Gollery