I was planning to compare a collection of four-dimensional sentences about Time found in "Engleby," by Sebastian Faulks (such as “Until we can navigate in time, I'm not sure that we can prove that what happened is real.”), and Van Veen's linear musings in ADA, plus their developments in the "Texture of Time," when I noticed a set of unprecedent quotation marks (underlined below):

‘But this,’ exclaimed Ada, ‘is certain, this is reality, this is pure fact — this forest, this moss, your hand, the ladybird on my leg, this cannot be taken away, can it? (it will, it was). This has all come together here, no matter how the paths twisted, and fooled each other, and got fouled up, they inevitably met here!’

‘We must now find our bicycles,’ said Van, ‘we are lost "in another part of the forest."’

‘Oh, let’s not return yet,’ she cried, ‘oh, wait.’

‘But I want to make sure of our whereabouts and whenabouts,’ said Van. ‘It is a philosophical need.’

To find what kind of quote they might be, I searched the annotations by the Kyoto Reading Circle, but got not the answer I was investigating:

153.32-33: 'in another part of the forest': Van already regards this forest philosophically as being both a temporal and spatial one, while Ada regards reality as something to enjoy. Cf."But, my love, my Van, I’m physical, horribly physical, I don’t know, I’m frank,qu’y puis-je? " (I. 25) 154.1: I want to make sure of our whereabouts and whenabouts: Though Ada is unwilling to leave the special merging of space and time that they have arrived at, Van insists on the philosophical need for distinguishing time and space--anticipating his lifework, Texture of Time.

The first one, a N-L archive message by Mike Donohue in 2005, highlights this simple sentence, placing it somehow in connection to the "whereabouts" of the crown jewels in Pale Fire !
LISTSERV 16.0 - NABOKV-L Archives https://listserv.ucsb.edu/lsv-cgi-bin/wa?A2...L...l... "Then the King escapes. He is dropped by Odon 'at the edge of the Mandevil Forest' (139).... Charles remembers 'the times he had picnicked hereabouts--in another part of the forest but on the same mountainside, and higher up, as a boy, on the boulderfield where Mr. Campbell had once twisted an ankle and had to be
carried down, smoking his pipe, by two husky attendants'."

The second one had all the trappings of a reference, but ... could VN, at this point, be indicating the title of Edmund White's collection of essays?* The dates are askew ( White's debut novel was published in 1973), unless it happens in Terra.

Edmund White - In Another Part of the Forest: : An Anthology of Gay Short Fiction (1994)

Google surprises!

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* - Wikipedia:

"His debut novel, Forgetting Elena (1973), set on an island, can be read as commenting on gay culture in a coded manner. The American/Russian novelist Vladimir Nabokov called it "a marvelous book."^[3]
[ '^ Edmund White, City Boy, 2009. ("Gerald Clarke..had gone to Montreux to do an interview with Nabokov for Esquire, and followed the usual drill...On his last evening in Switzerland he confronted Nabokov over drinks: 'So whom do you like?' he asked—since the great man had so far only listed his dislikes and aversions. 'Edmund White' Nabokov responded. 'He wrote Forgetting Elena. It’s a marvelous book." He’d then gone on to list titles by John Updike and Delmore Schwartz (particularly the short story “In Dreams Begin Responsibilities”), as well as Robbe-Grillet’s Jealousy among a few others.").]