NZ, unplanned hunt, is this worth going back for?

[Lazasaurus]

Hi everyone. Had an unscheduled look at a location today that I was driving by, due to the small tide window for access being perfect.

Unfortunately I had none of my gear on me due to being on another mission. I did however have a screwdriver in the car that measures 26cm's (just over 10 inches) that I used for a make shift scale. I didn't take the rock with me as it weighs approximately 50kg's (110lbs). I am unsure if it is plant or bone, or something else, which will derermine whether or not I go back to collect it.

The area is late Miocene, approximately 9 million years, mostly deepwater sandstone.

[Yoda]

@Doctor Mud may be able to advise further 

[Ludwigia]

Or @mamlambo

[RJB]

Looks interesting whatever it is?

 

RB

[Carl]

I'm seeing a piece of lignite here: wood. 

[MrR]

To my relatively untrained eye, it looks like something that was poured into that channel in the rock. It probably isn't, but it sure has the look. Good luck on ID.