It is the break up of the 'here' which necessitates the break up of the present duration.

Change in external nature is compatible with a prolongation of the present of contemplation rooted in a given standpoint.

What I want to bring out is that the preservation of a peculiar relation to a duration is a necessary condition for the function of that duration as a present duration for sense-awareness.
This peculiar relation is the relation of cogredience between the percipient event and the duration.

Cogredience is the preservation of unbroken quality of standpoint within the duration.

It is the continuance of identity of station within the whole of nature which is the terminus of sense-awareness.