Everyone,
 
I want to thank everyone for their helpful suggestions concerning how to
distinguish between a bottle cache and a bottle dump.  I think that while
some of the bottles are bottom up, by plotting the distribution and
frequency of the whole bottles this pattern becomes less significant. Many
of the bottles are lying on their sides and those that are bottom up may
have been deposited, as several people suggested, as part of a carton or
crate of bottles. The depth of the deposit and changes in the types of
bottles and their relative completeness suggests this deposit was not a
"quick time" event, but accumulated over a number of years. If so, it is
likely this is a dump. Dumps have been identified on adjacent slopes. The
bottles, ceramics, and other items in this feature are identical to those
identified for the surrounding dumps. As such, the "bottom down" bottles may
be fortuitous rather than significant indications of cache behavior. susan