rafters

The rafters that supported the roof of Belle Grove would have been assembled first on ground, then numbered and dismantled and reassembled in place atop the second story. Inscribed roman numerals were clearly visible on each piece of wood. While a metal roof adorned the house in the 20th century, nail holes indicated that shingles, likely split wood, were the original covering.

Features of note:
Up-and-down cut marks indicates the board was cut in an early nineteenth century saw mill.
tapered toward the ridge to lighten framing.
open mortice and tenon with treenail (peg) secures pairs of rafters at the peak.
absence of ridge board.

ridge board - a horizontal timber or member a the top of the roof, to which the upper ends of rafters are fastened. Rarely used for common rafter roofs until the late 19th century.

Definitions are from:
Lounsbury, Carl R. An Illustrated Glossary of Early Southern Architecture and Landscape. New York: Oxford University Press, 1994.