“Root-pop” bottle? Couldn’t find info

[EMMITT06]

Hey everybody, I’m new to bottle collecting but I found this one in a dumping pit near my home. The dumping pit has brought up funds from the 1910s to the 1970s but this was found buried deep in the oldest part. I tried to google it but couldn’t find any information on it whatsoever. The bottle says “Root pop Baltimore MD. Registered” on one side and the other side says “Athens Bott’g co. 9 FL. OZS.” Bottom has no markings, the side under the name says “98 B31”. Does anyone know anything about this soda? Can anyone give the bottle a date? Thanks everyone.