Suggestions on the best way to extract these shells?

[rock finder]

Hi! I'm very new to fossil finding and lucked across some fossil-filled rocks in central Kentucky a few weeks ago. I found these rocks in the median of I-75 in Kentucky, just before exit 87 (south of Richmond KY), where they had eroded off a sheer rock face that had been blasted out decades ago to make way for the expressway.  I'm not sure what kind of rock the shells are encased in, and the only tools i have at my disposal are not particularly well suited for the job (a generic 5/8" masonry chisel, a nail hammer, and a dremel with various carbide cutting bits). I'm working on getting some tools eventually, but for now that's what I'm working with. Any tips or suggestions about how to get these shells out of this stone with what I currently have? Is it just going to be impossible without better tools, and if so, which tools would you recommend for this job? 
I'm attaching a picture of the rock and shells in question, with letters A, B, and C above the shells i've noticed encased in here. I'm thinking A and B may have some promise, and maybe C too? I have no idea what I'm doing here so I'm open for any insights or suggestions

[Kane]

I would leave them in. They are very thin-shelled and largely supported by the matrix, so they would most likely break if you attempted to extract them.  If you want to reduce the matrix, you could always cut the block with an angle grinder if you can get your hands on one of those.

[Tidgy's Dad]

I agree, I think leaving them is safest. 

Extracting them would be nigh on impossible, i feel. 

They seem to be productid brachiopods, on the left a brachial valve and on the right a pedicle valve.