Preheat oven to 350 degrees F (175 degrees C). Grease one 8 inch square pan, and line with greased foil.
Combine brown sugar, flour, baking soda, salt, and rolled oats. Rub in the butter using your hands or a pastry blender to form a crumbly mixture. Press 2 cups of the mixture into the bottom of the prepared pan. Spread the jam to within 1/4 inch of the edge. Sprinkle the remaining crumb mixture over the top, and lightly press it into the jam.
Bake for 35 to 40 minutes in preheated oven, or until lightly browned. Allow to cool before cutting into bars.