(I shouldn’t have used the word “micro-plate” in my original post. “Terrane,” “micro-terrane,” or (for the bigger ones) “block” is more correct.)
The way exotic terranes are traded off between continental plates is one of the most fascinating topics in plate tectonics for me.
When I concurred completely with your post 2, I understood you were guessing “perhaps limestones” and referring non-specifically to metamorphism by saying “say, shales.” I didn’t take it as you were saying shales are metamorphosed from limestone, you obviously know better than that, you were just alluding offhand to sedimentary metamorphism in general, so I still think your original guess off of just the photographs was informed and astute.
Sorry, I was in a hurry with my rather terse response (wasn’t trying to be snippy).
The link you provided states the date as 1958. The link I provided is from 1976 (and I found a nice refined version in living color from 1979).
You’ll note the Kjf formations surrounding San Simeon were reassigned to the Tm in the later versions. Also, note the geological cross-section (B-B’) in the upper-right-hand corner of sheet 1. The line saunters right on by San Simeon point.
There is another point up the coast that is surrounded by Kjfmv. That would be Piedras Biancas Point.
A great resource are these two links The National Geologic Map Database and the USGS Publications Warehouse.
Thanks for your confidence in what I’d meant by that! You’re right, I should have been clearer in my phrasing – but I didn’t really mind njtt’s clarification.
To clarify further: I was taught that shale generally metamorphizes into slate, while limestone generally metamorphizes into marble. I’m sure there are all sorts of alternate pathways, but I presume these are still considered typical ones.
Ooh, thanks , I stand corrected. CalGeo needs to update their online maps 
Monterey it is. I think the lithology I mentioned would still be the same, though - chert-shale-sand interbedding?
Of those three, it looks like most of what’s in the OP’s photos is chert.
It’s really, really hard to say without being there. I’d need to see a hand specimen to be sure.
I agree that those photos do not have nearly a high-enough resolution to identify chert. However, from the Wiki on chert :
“Diatomaceous chert consists of beds and lenses of diatomite which were converted during diagenesis into dense, hard chert. Beds of marine diatomaceous chert comprising strata several hundred meters thick have been reported from sedimentary sequences such as the Miocene Monterey Formation of California and occur in rocks as old as the Cretaceous.”
Posted by someone who lives near and has spent time in the areas of the novaculite variety of chert in the Ouachita Mts of eastern OK, western AR - rather well-known to flint-knappers.