During heavy rain, a section of a mountainside measuring 5 km horizontally (perpendicular to the slope), 1 km up along the slope, and 1.5 m deep slips into a valley in a mud slide. Assume that the mud ends up uniformly distributed over a surface area of the valley measuring 0.3 km x 0.3 km and that the mass of a cubic meter of mud is 1900 kg. What is the mass of the mud sitting above a 4 m2 area of the valley floor?