This bottle was hand-blown in a mold that included a screw-thread lip portion. After the bottle was removed from the mold it was broken off of the blow pipe and the end was ground to allow a screw top to fit. Sometimes bottle collectors refer to this as "bust and grind".
This method of finishing a bottle dates from the 1850s to the late 19th century. Mason's 1858 patent was for a manufacturing method similar to this for home canning jars. This particular bottle was recovered during a controlled surface collection on a farmstead in Woodford County, Illinois.