The earliest American recipes for chowder called for fish rather than clams or shellfish and were prepared by layering the fish, salt pork, and biscuits (all shipboard staples) in a pot and cooking them for hours over a fire. This recipe calls for canned clams simply because those are the most easily accessible, but you can cook and use fresh clams as well.
Cooks' Note
Suggested Beverage: Hard cider, beer, or ale would be the best, but a crisp Gewürztraminer, Pinot Grigio, Sauvignon Blanc, or other light-to-medium white wine would also go well.