The "punctuation" on Punctuated Date 1795 Half Cents looks like a long comma between the 1 and the 7 of the date. While this seems like a perfectly normal place for punctuation, the "comma" was purely unintentional and is merely a die defect. The "comma" appears on the following 1795 die varieties:
Cohen 2a - Lettered Edge (the only variety that qualifies as the Punctuated Date, Lettered Edge)
Cohen 2b - Plain Edge
Cohen 3 - Plain Edge
Cohen 4 - Plain Edge
As can be seen above, the Cohen 2 variety bridged the transition from heavy weight (104 grains) to light weight (84 grains) planchets following a change in the law designed to reduce the cost of making Half Cents and Cents. The light weight planchets were too thin to received edge lettering, so they were issued with plain edges.
Sources and/or recommended reading:
"American Half Cents (Second Edition" by Roger S. Cohen, Jr.