The phrase "mark a boundary" is correct and usable in written English.
It means to establish or indicate a limit or dividing line between two things. Example: The new city ordinance marked a boundary between commercial and residential areas in the downtown district.
Such tests appear to mark a boundary between animals that display some form of consciousness and those that don't.
Fig. 17 Images taken on 19 October from the IR2 camera show a dark wavy feature at 1.74, 2.26 and 2.32 µm and mark a boundary between cloud masses to the north and south at some unknown altitude.
Delineation: The physical means used to mark a boundary or express the magnitude of an entity.
Testing blood was considered to mark a boundary between drug seller and health worker, shifting drug shop vendors into the category of endorsed professional.
The outlier marks a boundary.
They whispered incantations into each corner, marking a boundary to keep out evil spirits.
On first arriving at his new home, he is given a map of the neighbourhood, on which is marked a boundary beyond which he cannot stray.
Although Ms. Ledan was on foot and had used a sidewalk, Mr. Zuckerman suggested that the security booth marked a boundary line beyond which someone "could be trespassing".
Here, the prediction error from situational changes marks a boundary between constituents, triggering the updating process (Radvansky & Zacks, 2014; Zacks, Speer, & Reynolds, 2009), as suggested by behavioral and/or neurocognitive measures aligned with participants' identification of boundaries between events and/or discourse segments (Magliano & Zacks, 2011; Zacks et al., 2001, 2009).
They are termed extreme pathways because unique use of one of these pathways marks a boundary or extreme situation of the complete space of possibilities.
For this analysis a function was constructed which took positive values in EM and negative values in LM while intercept with X-axis marked a boundary between these groups (Fig. 7).
