Yes, people in the 1920s apparently thought that marshmallows, mayonnaise and whipped cream made a dandy salad dressing. Here's another Twenties salad, this one from an Ohio church cookbook dated 1923.
SALAD -- This is fine
1 head cabbage cut fine, small head; 6 marshmallows, diced; 8 pieces of pineapple diced; now take whip cream and mix with mayonnaise dressing and serve on lettuce leaves.
Regional cookbooks are a lot of fun, especially since there may be local names for ingredients that can cause the unsuspecting reader from a different place and time to boggle a bit. If you're from rural eastern Ohio or western Pennsylvania, you'll have no trouble figuring out what's going on with this next recipe; if you live elsewhere you might be a bit puzzled. (Hint -- although it's from the same cookbook, this one isn't a salad.)
STUFFED MANGOES
4 large mangoes, cut tops off and take seeds out; then brine of about one hour; fill with 1 lb hamburger; 1/2 cup of steamed rice; small onions; 1/2 teaspoon salt; then put the tops of the mangoes back on with tooth picks and boil in 1 qt. of tomato juice with large piece of butter; 1/2 cup sugar. Boil one hour.
If you haven't guessed, this is a recipe for stuffed peppers! The regional name for bell peppers in that part of the country is "mangoes" -- in fact, you can go into almost any grocery store in a rural area there and find signs in the produce section advertising "Mangoes" and "Fruit Mangoes".