From page 72[ed]:
> And on the other hand, if Mark received his Gos-
pel from Peter, why is it that the other Gospels have more anecdotes about Peter, including for example, Je- sus telling him, “You are Peter the rock, and upon this rock I will build my church”? Would Peter himself for- get such an incident? It gets worse. Mark shows no un- derstanding of the social situation in the Holy Land, making numerous errors that no one living in early first century Judea would have made. Interestingly enough, when you compare Matthew’s and Mark’s Gospels, one finds that the author of Matthew is constantly correcting Mark’s blunders about all aspects of Jewish society, re- ligion, the calendar, holidays, customs, attitudes – even repeated misquotes of scripture.
I'm afraid this is just not informative at all, and doesn't give me a good impression of the rest of the book.
Why did Mark not include it? The simplest answer is that he didn't think it was important. Mark is the shortest book -- there are lots of things that mark could have included and didn't. His implication is that somehow Mark didn't know where Peter / Cephas / Rock's nickname came from, which I find much more hard to believe than that he just decided not to include it. This is hardly the kind of evidence you can follow with "it gets worse".
But it gets worse. There's absolutely no detail here -- what social situation is Mark allegedly showing no understanding of? What kinds of "errors" is he making? I can't go and verify what he's saying, or consider the claim critically myself. Is Mark's change an "error", showing a basic lack of knowledge about the societal situation? Or is it a deliberate "contextualization", to make the stories accessible to a Greek audience without having to explain loads of irrelevant cultural background? No way to check and judge for myself; I'm expected to just take it on his authority.
And re the geographical "blunder" -- I someone in Cambridge, UK today said, "I'm going by way of Manchester to London", nobody would say they were committing a "geographical blunder". They'd understand that person to mean that they are going to first visit Manchester briefly, and then go to London.
This sort of thing is exactly in line with other things I've read claiming that Jesus didn't exist; I've never seen anything to make me think it's worth spending more of my time digging into.