Here is mine not as many files as yours!! Obviously the ones with no extension are subfolders.

/Volumes/GARMIN/Garmin/CustomMaps <- empty
/Volumes/GARMIN/Garmin/CustomSymbols <- empty
/Volumes/GARMIN/Garmin/Filters/Geocache/Quick Filter.gff
/Volumes/GARMIN/Garmin/GarminDevice.xml
/Volumes/GARMIN/Garmin/gmapbmap.img
/Volumes/GARMIN/Garmin/GPX <- emptied after backing up
/Volumes/GARMIN/Garmin/GUPDATE.GCD
/Volumes/GARMIN/Garmin/Profiles/Marine.gpf
/Volumes/GARMIN/Garmin/startup.txt
/Volumes/GARMIN/Garmin/system.xml