"Pictures From a Trip" is a first novel about the floating microcosm conjured up by extended travel, in this case by car. There is nothing new in that: Jack Kerouac's "On the Road" may be the fountainhead of recent American treatments, but the theme harks back beyond older forms of transportation (Huck and Jim's raft) to the picaresque origin of the modern novel in "Don Quixote."

Yet author Tim Rumsey does offer an interesting variation on this standard fare. The youthful, unnamed narrator, his brother Mark, and their blind friend Ben set off from the Twin Cities in search of dinosaur fossils. Rumsey's choice of quest-object is a shrewd one.

Shrewd but fraught with peril. Perhaps it was a foregone conclusion -- compelled by verisimilitude -- that the trio would not actually unearth a significant dinosaur find. Untrained young men, no matter how achingly determined and frisky, simply do not go out and dredge up miracles from picked-over post-OPEC soil. Yet Rumsey pumps up the reader's expectations and then deflates them by slow leakage in a way that borders on humbug. Worse, he fails to add some other plot device to keep them from bumping along the ground.

This leaves friendship as the novel's only source of buoyancy, and here the author fails egregiously. He states and restates that Mark and the narrator have an extraordinary intimacy but almost never dramatizes it. As for Mark and Ben, the best explanation of their palhood that Rumsey can muster is the narrator's concluding remark, "They pretty much had your basic immediate rapport." Later he walks into a kitchen only to find "your basic empty cupboard" and describes Mark's girl friend as "one fine woman . . . Blond, beautiful, and brilliant. She had all the bases covered, if you follow me."

This is trite, spiritless writing whose subliminal message is antinovelty. My story and characters are nothing new, the author is unwittingly signaling us, and you already know exactly what I'm saying. Then why bother, we might rejoin, to place ourselves in the hands of your basic cliche'-monger?

Every now and then Rumsey gives off a spark of originality, as in his observation that "an automobile trip across America is a moving foxhole with its own universe and its own time." For every one like that, however, there are a dozen hackneyed expressions (including the latest and glibbest euphemism for death, "that's all she wrote") and page after page of the unctuous, joshing patter that Stephen King has done so damnably much to revitalize. Rumsey is not even above transitions in mid-debate: "Just let me say this about the Longhorn." Altogether, his writing is sterile, puerile and dull.

All of which might be pardonable if "Pictures From a Trip" were a good story. But it rambles and shies away from conflict. When Mark's lady joins the trip for a few days, one's hopes rise: She and Ben seem to be working up to a sexual betrayal. Nothing comes of this. She goes back to her job, the boys to their picks and shovels. It's not giving anything away to disclose that Mark's life ends in an automobile accident -- Rumsey lets the reader know on the novel's second page. But even that incident has little dramatic consequence. The last time the two brothers were in contact, by phone, "Things were as cleaned up between us as they could be."

The PR people at William Morrow and Co., Rumsey's publisher, have seen fit to ply their Masters in Ballyhoo Administration full-tilt to "Pictures From a Trip": a 50,000 first printing, an ad budget of $60,000. By all means resist their blandishments -- unless you are in the market for a how-not-to book.