GDG- Artillery from Maine

[Carl Chatto]

Hello,

I've got a question I've been wondering about for awhile.

In some sources, artillery batteries from Maine are referred to as 
something like "Battery B, 2d Maine Light" or Battery E, 5th Maine 
Light", where the battery letter corresponds with the number [B-2, E-5]. 
Other sources show it as Battery B, Maine Light Artillery" and others as 
"5th Maine Artillery". I've got a letter written later in the war by an 
ancestor who referred to his unit as the 7th Maine Artillery. It seems 
like that's the correct reference. Does anyone have some other thoughts?

Thanks,
Carl