Hi Laura thanks for writing in. I know it's hard sometimes to work out the marks even if you are using a Jewelers Loupe.
Have another look at the marks that you can't make out under a strong magnifying glass or jewelers loupe with 10 X magnification in good light. Do you know what carat gold the ring is made from?
The "C" with the arrow going through it would be the sponsor mark. The jewelry firm that used a mark similar to the one you describe is -
WHITESIDES & BLANK (on 14K Gold, Manufacturing Jewelers, Newark, NJ, & New York, NY, USA) - ca 1890s - 1917.
