The amount of milk in MacHardie's glass changes between shots when he's alone with Eaton.
During the billiard game between Mr. MacHardie and Alfred, as MacHardie lines up for his shot, the red ball disappears.
David and Mary are drive along a country road in winter when Mary sees a boy, who is ice skating, break through the ice. They stop and David rushes to the pond. As he walks towards the hole in the ice, the ice easily breaks under his weight, and he wades toward the boy. He goes under, finds the boy, and brings him up. Standing in shoulder deep water, he hands the boy over to the boy's grandfather. BUT the boy's grandfather and Mary are both standing right at the edge of the ice, which does NOT crumble under their combined weight. So, even though one should NEVER go to the edge of broken ice, least one cause the ice to further break up and plunge one also into the water, the ice does NOT give in under the combined weight of three people (the grandfather, Mary, and now the boy). Further, David is able to get out of the water by hoisting himself up on the edge of the ice, just as he would if he were getting out of a swimming pool. Again, the ice, that was so brittle and fragile that it easily broke up when David initially walked into the pond, can now hold the combined weight of three people and support David as he puts further stress on the ice when he hoists himself up and onto what had been very fragile ice. Clearly, this "ice" is on top of something more solid and substantial than water.
The fate of the mill, which Eaton inherits after his father's death, is never revealed.
There's an establishing shot of the mill which shows a '59 Impala and some other late 50's cars.
Although the storyline at that point is set in the early 1950s, Natalie Benziger's Plymouth convertible is equipped with 1956 Hudson wheel covers.
The story begins in 1946, and advances into the early 1950s, yet all of the women's clothes and hairstyles, particularly those of Joanne Woodward, are strictly and relentlessly 1960.
It's never explained how Duffy knew where and when Natalie and Eaton would meet for their tryst.
Samuel has a heart attack after Eaton leaves the office. Eaton should not have been aware of what happened, much less, returned to the office and gotten his father to the hospital.
Eaton doesn't ask Martha's nurse how she knows who Frolick is and where he lives.