I bought a bunch of bones from the butcher but here is the deal. Some of the bones have pure marrow(the gooey fat stuff in the middle of the bone) but some have only a little marrow and brittle bone covering the marrow. so it looks like a core of gooey marrow which is covered by these brittle bone-like marrow which is covered by hard outer bone. of course they are not cooked but when i tried scooping out the marrow, these bone-like marrow started breaking apart but i cannot scoop them out as they are hard to get out.

Only thing to watch out for is if the bones are from weight bearing parts of large animals - these bones are extra hard and can potentially cause tooth fractures.

Raw bones are fine for dogs - marrow or not.
Just don't cook the bones so the dog isn't missing out on all the nutrients that will be taken away if it is cooked and for some meats (like chicken) it ends up turning the bone brittle causing digestive issues.

Leave the marrow in, and yes, they are safe. It's good for your dog's teeth and jaws to have to work at it.

just as long as the bones are raw, give them to the dog (one at a time)
you can freeze the extras for later.
if they have marrow in them, that is healthy for your dog to eat, but if the dog hasn't licked out the marrow or finished the bone in a couple days, then dispose of it so that the bone doesn't go rancid.

it's just fine for your dog to eat raw.

It's fine. I give my dog bones with marrow in it all the time and he loves them.