Question about arrow symbol next to mate symbol

Hi,

I have question about a symbol that is showing up next to some of my mate symbols in an assembly. It is a black arrow that points down and is normal to a horizontal black horizontal line with a dashed green line under the black horizontal line. I have attached a screen shot of the symbol below and it is next to the first three Coincident mates. What does this symbol mean? I searched the help file and the forum but did not find anything on it. I'm using SW2010.

Thanks,

Tom

SolidworksAssemblies