help with cretaceous unknown

[val horn]

two unknowns that i would like help with from early cretaceous arundel formation in maryland one large one small.  The large piece is ironstone that looks like it formed around a series of reeds or stems.  The photo shows it sitting on a 8 by 10 inch notepad.  It itself is approximately 12 by 4 inches.  The smaller piece is a thin section of ironstone with a oval section of stone/tooth/bone 1.5 cm by 1 cm with a dense cortex and a web like internal structure .  ID, Ideas and suggestions are welcome

 

 

[Darbi]

Hard to say. It also could be a burrow.

[EMP]

On 8/1/2020 at 3:53 PM, 10313horn said:

two unknowns that i would like help with from early cretaceous arundel formation in maryland one large one small.  The large piece is ironstone that looks like it formed around a series of reeds or stems.  The photo shows it sitting on a 8 by 10 inch notepad.  It itself is approximately 12 by 4 inches.  The smaller piece is a thin section of ironstone with a oval section of stone/tooth/bone 1.5 cm by 1 cm with a dense cortex and a web like internal structure .  ID, Ideas and suggestions are welcome

 

 

 

I don't think any of these pieces are from the Arundel Clay. From my experience the Arundel Clay is a drab-dark gray clay (sometimes with an arenaceous/sandy  texture), whereas these pieces are a more coarse ironstone/sandstone. My bet is that these are from the underlying Patuxent Formation, which is known for it's sandy deposits and sandstone concretions. 

 

The first specimen looks to be a piece of consolidated sandstone concretion from the Patuxent Formation, with sole markings indicating riverine deposition. 

 

The second is perhaps some kind of burrow. Rather hard to make out exactly.