After the subgrade has been finished to a uniform surface and rolled until thoroughly compact, a course of stone to be approximately 6 inches in depth, is to be placed or spread. This base course of stone may be large stone, placed and then broken on the street so that no stone will be larger than 5 inches in size. This base course of stone must be so placed and graded that it will be reasonably true and uniform with reference to the finished surface of the pavement. After being placed it must be rolled, with a heavy 3-wheel roller, until thoroughly compact and solid. Over this surface of large stone there must be spread a course of crushed limestone from 1¼ to 2½ inches in size to a depth sufficient to fill all the voids in the larger stone. This course of stone must be rolled until it is well incorporated with the larger stone. A light course of screenings must then be applied by being distributed over the surface uniformly with a sand spreader. No screenings are to be applied, except when they are dry, and only in sufficient quantities to partly fill the voids in the surface stone. The top course of crushed stone must be rolled to assist in working them down into the stone; and where the stones do not show, and are covered by the screenings, the screenings must be swept therefrom.