"he remarks on" is a grammatically correct and commonly used phrase in written English.
It can be used when describing someone's statement or observation about a topic. Example: During the meeting, John remarked on the current state of the company's finances, expressing his concern over the decrease in profits.
(At one point he remarks on the unpleasantness of dissecting corpses).
The writer's notes, indeed, are meat and drink to Frank: he pounces on them like a hungry cat, seeming more interested in the plans for a book than in the quality of the finished product; one can almost hear the pathos when he remarks on the regrettable paucity of author's notes for "The Brothers Karamazov".
Leone, he remarks on his way out, was only 60 when he died.
He remarks on the anachronistic nature of the futuristic vision he came up with which is so heavily entrenched in World War Two and the past.
Moving closer to the present, he remarks on our resemblance to chimpanzees; speculates on whether our predecessor, Homo erectus, had a religious sensibility; and examines how theories of child development shed light on language and music.
Craning for a closer look, he remarks on the author's boldness in writing such a slender volume with so many short chapters, providing "a new beginning each time, for which you ought to have a good reason".
When he remarked on her obliviousness after she chattered on one day about vertebrate anatomy to their neighbor — "Matson was totally bored," he informed her — there was no judgment, only pride that he had managed to notice.
At one point, between lunch and dinner service, he remarked on the increasing rate of injury among his kitchen staff.
He remarked on the trials of traveling alone and perhaps spraining one's ankle and being pecked to death by birds of prey.
He remarked on the Army's responsiveness.
He remarked on being bombarded with the same junk.
