Bone, tube, or plant?

[sTamprockcoin]

I found these at an Oriskany Sandstone exposure in Blair County Pennsylvania that is normally  overgrown. There was abundant crinoid & shell material around. There is no internal structure,  and the larger specimen seems to show some faint longitudinal striations. ID suggestions appreciated ad.  I was thinking Mud tube, filled burrow, cephalopod /shell cast, or plant bits.  I couldn't find any similar pictures in my resources. 

[Rockwood]

1 hour ago, sTamprockcoin said:

at an Oriskany Sandstone exposure

In  situ ? Any chance it could be a displaced and beleaguered artesia   ?

[sTamprockcoin]

Yes, In Situ (well, I didn't climb (scared of heights!) up to the outcrop but they were at the base with piles of similar matrix.) its definitely Devonian - Onondaga/Old Port Formation. The Cambria County Coal Fields are two ridges over (5 miles laterally) and then about 500-800 feet UP! I'm basically right at the base of the Allegheny Escarpment.

[GeschWhat]

Interesting matrix. I see a shell imprint in the second photo. My guess would be a burrow.