The Geico cavemen proved that Stone Age humor is best taken in small doses.

Director and co-writer Harold Ramis failed to take note. Ramis has comic talent, which he demonstrated in "Groundhog Day" and the golfer cult movie "Caddyshack." Those movies starred Bill Murray, who no doubt is glad he's not in "Year One."

This latest Ramis comedy begins in a village of prehistoric men and women and then morphs into a Biblical buddy movie.

Jack Black and Michael Cera bring their trademark screen characters to the proceedings, and Cera fares the best.

Black plays Zed, an inept hunter who is more likely to spear his companions than his prey. Cera plays Oh, a food gatherer who doesn't have the machismo to be a hunter.

Zed tastes the fruit of the tree of knowledge, which never lives up to its claim. He doesn't get any smarter, but his misguided opinion of himself is needlessly inflated. The tribe casts him out of the village, and Oh decides to tag along. They first bump into Cain and Abel and witness the inevitable fratricide. They then they save Isaac from his father's knife.

Two things drive the duo from Abraham's tent. The first is the prospect of circumcision. The second is a graphic description of Sodom. That's where the thus-far elusive women of their dreams are headed as slaves, but Zed and Oh are intrigued by the action as much as the prospect of a rescue. Juno Temple is feisty and cute as Eema, the object of Oh's infatuation. June Diane Raphael is Maya, the cave woman who makes Zed leer.

In Sodom, they find sin city, but it's so drought-stricken that the few remaining virgins are cast into a furnace as a sacrifice to appease the gods. Zed and Oh's fortunes take a roller-coaster ride as they try to save the women and cope with the wicked ways of their new home. Oh is chased by a lecherous high priest played by Oliver Platt, and Zed catches the eye of the princess.

Comedies that require their characters to wear archaic costumes are an iffy proposition. The last funny movie to involve a toga is probably "Animal House."

In the right hands, vulgarity can be funny, but here it seems more like desperation than humor. Potty and sex jokes abound, but they're more discomfiting than funny.

Black and Cera strive to put some life into the material. Black is revved to the red line with his dominating physicality. It's old stuff, but it's the appropriate counterbalance for Cera, the dork who meets the travails he encounters with a sense of ironic inevitability.

Keep your fingers crossed and hope there won't be a "Year Two."

"Year One" H ¹₂

At Carmike 10 at Tanglewood Mall, Salem Valley 8 and Valley View Grande 16. Rated PG-13 for coarse humor, language and violence. One hour, 40 minutes.