Sift together the flour, baking soda and salt. Rub or cut in the butter. Add the sugar and rolled oats. Mix it together well. Spread 1/2 inch of crumbs in a greased 8 inch square pan. Pat to make smooth.
To make the filling:
In a saucepan boil the dates, brown sugar and water together until the dates are soft enough to be mashed with a fork, adding sufficient water to prevent scorching. The mixture should be of a jam-like consistency. Let cool before layering over the crust.
Cover the crust layer evenly with the cooled date filling. Cover with the remaining crumbs. Pat to make smooth.
Bake for 30 to 40 minutes or until pale brown. Leave the squares in the pan until they have cooled, then cut into squares.