The task is about reading the given story and question, then finding an answer to the given question. Based on the passage provided and the given question, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
Q: story: CHAPTER XXX

FERN Mullins rushed into the house on a Saturday morning early in September and shrieked at Carol, "School starts next Tuesday. I've got to have one more spree before I'm arrested. Let's get up a picnic down the lake for this afternoon. Won't you come, Mrs. Kennicott, and the doctor? Cy Bogart wants to go--he's a brat but he's lively."

"I don't think the doctor can go," sedately. "He said something about having to make a country call this afternoon. But I'd love to."

"That's dandy! Who can we get?"

"Mrs. Dyer might be chaperon. She's been so nice. And maybe Dave, if he could get away from the store."

"How about Erik Valborg? I think he's got lots more style than these town boys. You like him all right, don't you?"

So the picnic of Carol, Fern, Erik, Cy Bogart, and the Dyers was not only moral but inevitable.

They drove to the birch grove on the south shore of Lake Minniemashie. Dave Dyer was his most clownish self. He yelped, jigged, wore Carol's hat, dropped an ant down Fern's back, and when they went swimming (the women modestly changing in the car with the side curtains up, the men undressing behind the bushes, constantly repeating, "Gee, hope we don't run into poison ivy"), Dave splashed water on them and dived to clutch his wife's ankle. He infected the others. Erik gave an imitation of the Greek dancers he had seen in vaudeville, and when they sat down to picnic supper spread on a lap-robe on the grass, Cy climbed a tree to throw acorns at them. , question: where did the picnic take place?
A:
south shore of Lake Minniemashie