- ―Mr. Slate
Mr. Slate (known in earlier episodes as J.J. Granite or Mr. Rockhead) is Fred's boss at the Bedrock Quarrel and Gravel Company (later known as Slate Rock and Gravel Company) and a fictional character of the original series, The Flintstones and the rest of the franchise.
Mr. Slate is austere, strict, no-nonsense, serious, negative and hot-tempered. He often is not impressed by Fred's antics and amateurish blunders and often fires him only to give him his job back in the end.
He is a tall and stout caveman with fair skin, tan stubbles, black beady eyes and is nearly bald, having only two hair strands on his head, and wears a pair of black glasses with circular lenses. He wears a loin-cloth with a tie in various colors which hangs down to his knees. When he was a kid, known as Nate Slate from The Flintstone Kids, he had blonde hair.
In the 1994 film, Mr. Slate is still the owner of the company, but has a minor role in the film. His villainous Executive Vice President, Cliff Vandercave, concocts a plan to build faulty machinery to quadruple the company's profits but which will fall apart after Cliff has stolen Slate's money and fled the country. Cliff makes Fred Flintstone the Vice President of the company and tricks him into firing all the workers, framing him for embezzlement. Slate's reaction to this is unknown, and it is also not known whether it is he who calls the police to pursue Fred.
At the end, when Cliff is defeated and trapped in concrete, Slate congratulates Fred for "ending the Stone Age" and attempts to promote him to President of the company's concrete division, but Fred, happy with his own job, politely declines, and requests his old job back, along with two weeks holiday. Slate accepts, and his last line is "There goes the best executive I ever had."
- It was either a continuity error or a running gag that in each episode where Slate's first name was mentioned, it was different: Sylvester, Nate, Oscar or George.
- The only change of appearance was that his hair color could be seen.
- In the episode, "Moonlight and Maintenance", Mr. Slate has only two large tufts of dark hair behind his ears.
- Mr. Slate appeared as a supporting character in the 1995 series, Johnny Bravo, in the 2004 episode "A Page Right Out of History".
- In "Fred's New Boss", Mr. Slate was said to be Barney's uncle. No mention of this was made ever again.
- In The Flintstones comic strips (which ran for 37 years) Mr. Slate was depicted with his earlier mustached design and still bearing the name "Mr. Granite" for the majority of the comic strip's run, despite his character receiving a finalized name and design during season 2 that remained with him for the rest of the franchise. It wasn't until the late 80s that Mr. Granite was finally updated to Mr. Slate.
- In these comic strips, Mr. Slate was also given a unique and recurring secretary character by the name of Miss Strongstone.