A pair of French Second Empire (recognizable by slanted roofs and dormer windows) clapboard houses built by Robert and James Cunningham in 1866 have somehow survived at 312 and 314 East 53rd just east of Second Avenue on a block otherwise dominated by brownstone buildings, which came along about 20 years later. In 1866 they were nestled at the city’s northern extent and likely were surrounded by fields and forests.
Oddly, #312 was designated a NYC Landmark in 1968 while #314 had to wait until 2000; my guess is that #314 is more heavily altered than its neighbor. #312 has a NYC Landmarks plaque, while #314 doesn’t.
Daytonian in Manhattan has a comprehensive account of these two fascinating buildings, along with an interior shot of #312.