In a Collins glass full of cracked ice, add the lime juice and shell, tequila and cassis. Stir. Top with ginger ale. Add a straw.
Drinking the Devil's Acre uses 2 oz blanco tequila, 1 oz lime juice (consistent with the lime juice and wedge), 3 oz ginger beer (rather than ginger ale) and 1/2 oz crème de cassis, which is floated on top.
From Trader Vic's book of Food and Drink, adapted by Smuggler's Cove
Trader Vic's Pacific Island Cookbook, pg 186