Age Of The Ridiculously Large Mint Mark
The San Francisco liberty seated no motto quarters from 1855-1865 (none were issued in 1863) feature a mink mark disproportionately large compared to the font size of the legend. The no motto half dollar mint mark is also large. The 1859-s dollar is more proportional. I'm not sure if anyone has studied it, but I wonder if the same "S" punch was used for all three denominations.
Here's my run of quarters. Despite it's reputation (and price), the 60-s isn't nearly as rare as the 64-s, which I consider the rarest no motto S mint quarter. I have since replaced the 65-s with a better coin which I'm still waiting on from a recent sub.
There's also an interesting large S over small S variety in 1856. I'm not sure what punch the small S was used for, probably the quarter eagle or gold dollar.