AS A CHILD I HAD a very literal mind. I swallowed stories whole. I read for the plot alone and was jolted to reality only by inconsistency. I never understood how so large a child as Alice fell down a rabbit hole, but the author said she had and so I went on reading, trusting she would meet a rabbit equal to that hole. When she didn't, it bothered me. I discussed the problem with my brother, who was 10 and wiser, and he decided she must have fallen into the ventilator shaft of an abandoned coal mine -- and the author just thought it was a rabbit hole. I could accept that, but I read on then with suspicion, wary that the author might blunder again.

What I required of fantasy was merely that the author make his or her imagined world have logic. It could have its own physical laws, but it had to be consistent.

Barbara Cohen's world in Unicorns in the rain is straight from Genesis 6:11 -- "The earth also was corrupt before God, and the earth was filled with violence." She writes convincingly of a time when no one goes out alone at night for fear of roving gangs, when people all carry guns in self-defense, and when most wear helmets like soliders under fire. It's a time when people are so laid back and mellow that the only feelings left are greed, ennui and hunger.

The younger narrator, Nikki, takes her world for granted, having known nothing else and not being given to moral judgments. She has somehow reached the age of 18 with her sense of humanity warped but intact. On a dreary train ride to spend the holiday with her grandmother (who insists Nikki call her "Maureen"), the girl sits next to a friendly boy who invites her home to dinner with his family. Grandma Maureen won't be home until midnight, so Nikki warily accepts.

The boy's home is beautiful, but odd to Nikki in that a father dominates the household of wife, three sons and two daughters-in-law. They run a wild-animal farm and Nikki loves animals. Dinner is delicious; it looks as if it's going to be a pleasant visit until she learns the father believes God has spoken to him and warned him of The Flood to come. Since she has heard of God only through Anthropology I and cuss words, the father's beliefs don't immediately upset her. But then it starts to rain.

Cohen allows her characters to say something when they talk, instead of condemning them to the constant wisecracks prevalent in books for this age group. I liked the promise of her story and think young readers will enjoy it. They may find themselves wondering what they would do in Nikki's world, but a child who looks for logic might be trouble by the presence of unicorns among the elephants and orangutans.

There's a surreal quality to The Norwood Tor, by Michael Bradley. At an unknown town in an unknown part of the country, Jeremy Spiller climbs aboard a moving train. Hands pull him to safety just as he is about to be crushed by a passing freight. The owners of the rescuing hands appear at first to be children; then Jeremy sees they are midgets. A friendly pair, they welcome the boy aboard their "Whimsy-Circus" train.

As the train rolls on, the reader learns that motherless Jeremy has run away from an uncaring father to find his brother Paul -- who is at a place called Norwood and in serious trouble. Paul's last letter says, "Forget about me, Jer. Stay away from here. I mean it, don't ever come. . . ." -- a sure way to get a loyal little brother to go find the only person in the world he cares about.

The train is full of the Whimsy-Circus troupe, many of whose members change constantly, as in a dream. Jeremy slowly learns that these people may be involved in his brother's disappearance. His dream to find Paul is realized with their aid; or is it?

The key word here is whimsy. Bradley evokes dream-like sensations, but characters of whimsy -- "subject to erratic behavior and unpredictable change" -- become confusing to the reader. Also, these figures have an unfortunate tendency to talk in riddles, to hint, but seldom do they say anything definite that might end the dream. Readers who do not question the size of rabbit holes and who enjoy elaborate games may appreciate the intricacies of this book. CAPTION: Illustration 1, Jacket illustration of "Unicorns In The Rain"; Copyright (c) 1980 By Ruth Sanderson; Illustration 2, Jacket painting of "The Norwood Tor" By Livia Audi