Identify these fossils/minerals

Factual Questions
1

I just returned from a camping holiday in North Yorkshire and a couple of days of this was spent on the remarkable beaches there; much of the coastline includes jurassic limestone, shale and clays, so we did find a few fossils, including ammonites, belmnites and a beatiful sea-worn boulder of some hard, deep red red stone that was uniformly studded with perfect bivalve shells - unfortunately, this was so large it could only just be moved by hand, so I was not able to bring it home.

Anyway, we spent the last day at Reighton Sands, right in front/on top of the famous Speeton Clay - my son found an excellent ammonite imprint, and there were many people hacking and digging at the cliffs - mostly pulling out fairly soft, crumbly specimens and destryong them in the process - I confined myself to searching the beach and foreshore. I returned with a number of interesting pieces, but here are a few that I can’t quite identify.

Specimen 1: front and back
I’m aware that certain nonliving mineral growths often give rise to ferny or feathery formations and this may be simply one of them, however, it is quite a substantial formation within the stone; the ‘stalk’ part runs right through the piece and forms the small semicircular shape on the back

Specimen 2: front and end
This one looks more impressive in real live than as depicted here; it’s a hard greyish pebble that, when viewed from the end, bears a very regular, perhaps even concentric, pattern of polka-dots, however, the worn sides of the pebble show that these dots are in fact the ends of cyclindrical structures that go all the way through the piece.

Specimen 3: front and end
At first glance this one looks just like a piece of sedimentary rock, however the striations within it are quite regular - more like woodgrain or the tooth of a large herbivore, especially on the end view. Plusthere was nothing else remotely like it nearby. It may just be a bit or innocent rock though.

Can anyone assist with identification of these? Particularly the first two.

2

Except for size, 1 looks a lot like an impression from the spinal plates of one of these Megasaurs.
OTOH, Godzilla’s plates also resemble the suture lines of some Ammonites. Can you tell if the pattern extends into the rock? If it’s just on the surface, you might be looking at a scar from a modern holdfast. Crinoids had holdfasts too but, for what it’s worth, I’ve never seen one that looked like that.

3

As far as I can tell, the only part of specimen 1 that extends through the rock is the ‘stalk’; the ‘fronds’ are not unmeasurably thin, but judging from the appearance of the part where they extend over an eroded edge (top right), they are no more than a few millimetres thick.

All observable features of the specimen are consistent with it being composed of about five or so fairly thin feathery fronds branching radially from a central stalk - of course there’s no easy way to tell how much of the original structure is still present; we may be looking at a very small slice of something much bigger.

4

Specimen one does strongly resemble an ammonite suture like Squink says. It appears to be eroded to the point where none of the original architecture remains, just an oblique, non-representative portion of the original.