On the bottom of a 5-gallon water bottle with cork closure is this maker's mark, which is a capital "M" in a shield. Not readily visible is a number " 24 " in the right lower corner of the shield. Bottle is a Los Angeles Arrowhead Water bottle.

So, who made the bottle?

Ans: Monarch Glass Company in business in Compton, CA (southern Caliornia) during the 1920's. It all fits :-)