A dam 800 feet long and 55 feet high might be erected across a gorge about 1 mile south of Petersburg. There would be formed a lake of about 1.247 square miles, or 800 acres in extent. The hamlet of Petersburg would be submerged, but the damages from the destruction of improved property would not be very great, as the improvements and the land are not especially valuable. This reservoir would have a capacity of about 964,000,000 cubic feet and the surface would be at a height of 800 feet above sea level. The alternative plan, that of using a longer stretch of the valley for reservoir purposes, would involve the construction about 1 mile below Lower Longwood of a dam 1,300 feet long and 110 feet high. The reservoir thus formed would be 1,900 acres in extent and contain approximately 3,447,000,000 cubic feet. The drainage area above this dam is limited, and if the reservoir were drawn down to an amount equivalent to 15 inches upon the drainage area there would still remain an enormous amount of water which could be used in a compensatory way to tide over dry seasons. _Splitrock Pond._--By erecting a dam 550 feet long and 30 feet high across a gorge at the outlet of Splitrock Pond, a lake could be formed having an area of 625 acres and adding to the present storage capacity of the lake an amount approximately equal to 475,000,000 cubic feet, equivalent to 38.75 inches on the drainage area. Thus it is seen that if this reservoir were drawn down an amount equivalent to 15 inches on the drainage area, which would without doubt give sufficient protection from all floods, there would still remain a storage capacity of 23.75 inches for compensating purposes in addition to the amount now available in Splitrock Pond. This project is one of the most attractive in the Rockaway Basin, as the damages which would be caused by flooding would be, comparatively speaking, nil. The property is, however, now owned by the East Jersey Water Company, and is prized highly as a reservoir site by that corporation. UPPER PASSAIC BASIN. _Millington reservoir._--There is an area of swamp land, comprising a part of the drainage area of upper Passaic River above Millington, which is known as Great Passaic Swamp. It is bounded on the south by a long, narrow trap ridge known as Long Hill, the summit of which ranges from 400 to 500 feet in elevation, or roughly 200 feet above the border of this swamp. To the northwest the land rises gradually toward Trowbridge Mountains, while to the northeast is the terminal moraine. The outlet of Passaic River at Millington is by a narrow gorge, which offers natural facilities for the erection of a dam.