The following sentence is from Frankenstein. Does the boldfaced prepositional phrase describe the time at which the speaker was seized with the nervous fever, or the time at which he remembered the nervous fever? Two paragraphs ago, the speaker said, "Two years had now nearly elapsed since the night on which he first received life," so I suppose that the time represented by the utterance two paragraphs ago is the time referred to by "at the time that I dated my creation." In other words, that's when he remembered the nervous fever. But the problem is, the "and which" sets up the border between two relative clauses and confines the prepositional phrase to the first relative clause. Is there anything wrong here?
I remembered also the nervous fever with which I had been seized just at the time that I dated my creation, and which would give an air of delirium to a tale otherwise so utterly improbable.