One of Michael Crichton's other novels was Congo. Its main plot is that there is a region in the African Jungle were unique diamonds can be found. These diamonds can be used in computer processors as super conductors. Three teams swarm to the jungle to excavate the site. This site is also the location of a fictional city Zinj. But the crystals are projected by a herd of highly dangerous and intelligent Gorilla's. The plot turn into a heroic battle for survival.
The novel was written in 1980, it was only adapted into a movie after the succes of Jurassic Park. The film version wasn't a succes. It was nominated for Worst Picture, Worst Director, Worst Supporting Actor, Worst Supporting Actress, Worst New Star, Worst Screenplay and Worst Original Song.
What has this to do with Jurassic Park???
Well, I always said that Isla Sorna (even with all the other 5 deaths) are far to small to sustain a dinosaur population of multiple species. DeSalle and Lindley calculated in their book The Science of Jurassic Park And The Lost World or, How To Build A Dinosaur that you need a reserve as large as Berkshire to accommodate the population of the first movie. JPIII and TLW show a much larger population.
Therefore, IF a new Jurassic Park movie is made, the dinosaurs have to be shipped to a larger preserve. Otherwise they would've been extinct by now. This problem was adressed in the Jurassic Park novella Jurassic Park Adventures: Prey.
But where on Earth is enough space for dinosaurs?? Since there isn't an unpopulated island that big, they have to move to a mainland preserve. This is the best candidate:
In central Africa there is a large lake named Lake Chad. From the 60s until now it it shrank as much as 95%. Manny lush forests and plains turned into deserts. Since it provides water to more than 20 million people living on the edge of the Sahara Desert the UN has made manny plans to stop the shrinking of the lake. One plan is to make a channel from the Oubangui river through Central Africa to the lake. If the Lake grows again to it's original size than there a HUGE plains of desert lands that become fertile again. But such a channel would cost at least 9 million euro, and the UN can't affort that.
So, the premis of Jurassic Park IV could be that InGen pays for the channel. The lake grows, the desert turn into a Garden of Eden and InGen populates the new Jungle with Dinosaurs.
But once we have created this Lost World, what story could interest an audience???
Maybe the main plot of Crichton's novel Congo could be used. If this is succesfully done it would finally give honour to Crichton's forgotten novel.
An expedition of the Earth Resource Technology Services Inc. in the new Dinosaur preserve discovers ruins by accident. It are the ruins of the Lost City of Zinj. It had been barried under sand for thousands of years, but it has resurfaced after the desert sand was washed away. They also discover the prefect diamonds. They send video material to Houston.
The group is attacked, but not by Gorilla's like in the novel but by... (guess what) Troodons.
From that point the plot must be the same as the novel. Ofcourse, in the novels the highly intelligent Gorilla's are the constant threat, here it are highly intelligent Troodons and Raptors.