That said I would state that Tristram and Martha were married about 1739.Children:
Martha b. 1740 Samuel b. 1742 Mary b. 1744
The rest of the children may not be in order:
Tristram b. 1746 (died in 1825 and married a woman born in 1747) Richard b. 1748 (died in 1815 and married a woman born in 1750) William b. 1750 Leah b. 1752 Elizabeth b. 1754 (possibly the Betty Pinkham who married Andrew Young at Gilmanton in 1789) Grace b. 1756 Abigail b. 1758 (married JosephRunnels in 1780, very likely the youngest)
So how does that timeline work?I realize that puts Leah out of place in the order, but there's no way to squeeze her in before Mary and after Martha (unless Mary and Martha were twins, which is possible, but that's complete supposition).