Mildred Wart 
Swamp Island (Serapis Classics) 

Penny and Louise go to a nearby swamp to gather flowers for a banquet and manage to lose Louise’s dog during the trip. They plan to go back, but first they learn of an escaped convict. Penny knows the convict would hide in the swamp, thus giving her another reason to search the swamp. While dodging dangerous animals, the girls discover Louise’s dog, the convict, an illegal immigrant, and an illegal alcohol distillery in the swamp.