The Last Dinosaur (1977)

Masten Thrust Jr. (Richard Boone) is an oil tycoon and big game hunter.  He is more proud of the big game hunting, of course.  His company has recently been using a laser on the tip of a manned submersible that bores into the earth beneath the Arctic in search of oil.  A recent exploration found a hidden valley that was heated by a volcano.  Of the 5 crew, only one returned: Chuck Wade (Steven Keats).  He claimed the other 4 men were devoured by a Tyrannosaurus Rex!  Thrust himself will lead an expedition to both confirm the claim and study the animal.  The team is Thrust, Wade, Frankie Banks (Joan Van Ark) the photojournalist, Dr. Kawamoto, and Bunta the Masai tracker.

The hidden valley proves to be inhabited by various dinosaurs - most of which make a quick appearance before vanishing for the remainder of the film - and long extinct plant life.  After setting up camp, Thrust's next order of business is to find the T Rex.  He brings a rifle.  For their protection!  Sure enough, they come upon the dinosaur, who sounds uncannily like Godzilla, and the rifle is required.  Thrust blows the shot then tosses the jammed rifle aside like it is worthless.  Gah!  Are you mad?  The little band flee.  When they return to the camp, Dr. Kawamoto has been devoured and their submersible is gone!  Worse still, in addition to dinosaurs, the valley is inhabited by primitive humans who decide to compete with them.  Worst of all, Thrust gave orders that no rescue should be launched for them.  If they were not back in five days, they were to be presumed dead.

The special effects are extremely dated.  The dinosaurs are clearly just actors in rubber suits.  The characters are okay.  Thrust is single-minded in his desire to kill the T Rex.  I was horrified when Thrust, who should have known better, tossed aside the only rifle in the valley.  It's just a jam!  Take it back to camp and clean the gun!  It really damaged his character, making him look like a blithering idiot.  Bunta has no lines but his size and daring making for an interesting character; he's kind of like Chewbacca.  Wade is the voice of reason but also a complainer.  He and Frankie both take on the complainer mantle.  Thrust had been adamant against taking a woman on safari but was 'convinced' after the two spent some time together.  Huh.  There is something of a love triangle as Wade and Frankie are drawn together while in the valley.

Just so-so.