Preheat the oven to 400 degrees. Lightly grease a muffin tin. In a large bowl, combine the flour, baking powder, sugar, and salt. With a pastry blender or two knives, cut the margarine to make a well in the center. Put the eggs in a small bowl; add it to the mixture all at once into the well in the flour mixture, stirring it until it is just moist. Fold in the Blackberry's. Bake for 25 to 30 minutes or until golden brown. Remove from oven and immediately remove from pan. Serve warm or at room temperature.