Answer:
causal transition
Step-by-step explanation:
The causal transition is characterized as an expression that allows the sentence to have a cause-reason effect, that is, the sentence states that a certain thing happens, because such a thing exists.
In the phrase "Later on, in the fall of the year, he saved John Thornton's life in quite another fashion" shows an example of a casual transition, through the expression "Later on", which establishes a relationship between the other parts of the phrase, which present themselves as a reason/cause.