In the summer of 1968, Peppermint Patty became the tent monitor for three (very) little girls, during a summer camp session. They were known as Clara, Sophie and Shirley. Clara looked VERY similar to Marcie, with two differences: she was a little shorter, and you could see her eyes through her glasses. You can see her at United Media's Peanuts Website - the first comic down.
Peppermint Patty returned to camp in 1971, and THIS year, she met another girl who looked even more like Marcie, because her eyes were hidden by her glasses (even I haven't found out how she can see through them). She also copied Marcie's habit of calling Peppermint Patty "Sir" (also at the website above, but in the second comic down). However, her name went untold until an adventure later that year, when she went to "Peppermint" Patty's house, and finally gave her name as Marcie.
However, I think the best person to hand the debate over to is my friend Derrick Bang at Marcie vs. Clara. He has some great information on the subject.
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