(a) "S-1" Special. Large public or semipublic land holdings, land which is suitable for noncommercial recreation, areas to be kept open for highway interchanges or take-off or landing of aircraft, low lying land subject to periodic flooding or land to be kept open to protect the source of Municipal water supply.
(b) "A-1" Agriculture. Land which is level or gently rolling and is best reserved for agricultural and other rural purposes.