Avocado Watermelon Lime Parfaits

Description
This recipe came from an estate sale. I obtained it when I purchased the family collection from the Ritchie Estate in Balch Springs, Texas in 1984.
 * Contributed by Catsrecipes Y-Group

Ingredients
1/4 small watermelon 1 pint lime sherbet 1 large avocado peeled and sliced 12 ounces bottle 7-up

Directions
Make melon balls of watermelon. Alternate small scoops of lime sherbet, melon balls and avocado slices in chilled parfait glasses then pour 7-up over mixture immediately before serving.