By 1857, the original Twin Lights at Navesink structure had fallen into disrepair, and a new Twin Lights at Navesink was constructed. First lit on May 1, 1862, the new lighthouse featured a castle-like brownstone structure with a square tower on the south end and an octagonal tower on the north end, 228 feet away. Each tower was outfitted with a first-order Fresnel lens capable of producing 8,000 candlepower, making Twin Lights the most powerful lighthouse in the United States at the time.
Sources: http://lighthousefriends.com/light.asp?ID=376
http://www.twinlightslighthouse.com/history.html