"Relic" was published only twenty years ago but it reads like it's from at least a decade earlier - less "Jurrasic Park", more "Poseidon Adventure".
"Relic" is based on a complex idea on how a monstrous creature might evolve but the exposition of the idea is clumsily done. Most of the book reads like a "Monster In The Basement" slash/horror piece except without the exploitative gore.
It was a fun as a leisurely "remember when they wrote books like this?" read, but wouldn't really count as a thriller today: the pace is too slow, the build up goes on for too long, one of the main action sequences happens off-stage, and there are too many characters.
It does have some good "Saturday Matinee" moments: there is a rude, cowardly, stupid FBI Special Agent to hiss and boo at; an urbane Southern Gentleman, FBI Special Agent to cheer for (although, if you do, he'll look modestly away and say "I did nothing particularly praiseworthy), a rough but brave NYPD Lieutenant to save the day; venal academics who suppress the truth and pay the price for it and brave, politically correct academics (an older prof in a wheel chair and his young, female grad student) who pursue the truth and save the day. Finally, there is The Creature. It's a well thought through Creature, probably the best thing in the book, but it still screams werewolf meets lizard man.
The structure of the book creaks: there's a slow opening in Africa, then another opening in New York, that explains everything that happened in Africa, then the main action when The Creature attacks, then a "Six Weeks Later..." section to wrap up the odds and ends, then an Epilogue that finally (but still slowly) explains the plot and set up a the sequel.
Oddly, one of the things that sticks with me about the book was how annoyed I was at the fictional New York Natural History Museum's lack of care of the items its patrons had pillaged throughout the world. It seems absurd to me that artifacts stolen from the Sioux, the Inuit and the Navajo would be labelled "Anthropology", but that's the kind of dissonance that makes reading period books interesting.
Another minor irritation was the authors' use of "shined" instead of "shone" and "knealed" instead of "knelt". Why would an editor let that usage pass, except in direct speech?
"Relic" was made into a not-bad creature feature called " The Relic". The plot remained much the same, the number of characters was reduced and, for reasons I don't understand, the action moved from New York to Chicago.