Cream butter, beat in brown sugar, gradually beat in flour, salt, baking soda and mix well. Stir in oats. Pack 1/2 the mixture into bottom of greased 9x12 pan. Spread the preserves over bottom of crust - not quite to the edges. Spread remaining crust mixture over preserves. Bake in a preheated 400 degree oven for 20-25 minutes until browned. Remove from oven and cool in pan placed on rack. When cool, trim off 1/2" around sides if the edges are too crisp and cut into small squares.