Plant, Bone or Stone

[4thgrdtcher]

This item was uncovered while excavating my basement in 2007.  After watching a series of videos from the Illinois Geological Survey last year, I believe it is petrified wood of some early tree's growing in Northern Illinois between glacial periods.  it weighs 17.2 pounds and its about 10 inches tall.  It has a large flat area and another smaller flat area on its opposite.  I don't see rings as you might see in tree stumps which is concerning.  Rather it has vertical lines on most of it sides with interesting crevasses like an old tree limb might have.  It is appears broken at the top with an almost rotted core look to it.  Can you help me identify and age this item?  

[Rob Russell]

Welcome to the forum, teach.  

Its hard to tell from your photos (they’re a bit out of focus) if that’s pet wood, or not. It’s possible. It definitely looks like it.  Petrified wood can be found in Pennsylvania aged terrestrial sediments in many locations around the state.  If it was indeed found in glacial til north of I80 I’d be less inclined to thing it’s a fossil, opposed to a geological specimen. 

I will be interested to see what the experts say. For I am just a novice, and a long time 

collector here in Illinois.  Cool piece!

 

Rob. 

 

Edit:  perhaps if you look at a sediment chart for the state of Illinois you can determine what the age of the rock is below your feet. Anything Silurian and older lessens the likelihood of that being pet wood, IMO. 

Good luck!

[Rockwood]

Sedimentary rock I'm afraid. Your ring worries are well founded.

[Mark Kmiecik]

That is one really cool sedimentary rock, most probably glacially deposited in the area unless brought to the area by a person. Basement excavations often uncover what people have deposited there that they brought with them from other places all over the globe. For instance, it may have been used to shore up the walls of a root cellar and eventually your house was built over the site. However, my vote is still "glacial erratic". Northern Illinois is glacial erratic heaven.

[4thgrdtcher]

Thank you for your input.  I have another question about this "rock". 

Why was this rock the only rock to come out of the ground all white and calcified?  It clearly didn't match any of the 1000 other rocks from the basement excavation.  Thank you,  Tom

ps I didn't do any cleaning to this rock so no sand or silt was really attached to it.  

Edited July 1, 2019 by 4thgrdtcher

[Mark Kmiecik]

5 hours ago, 4thgrdtcher said:

Why was this rock the only rock to come out of the ground all white and calcified?  It clearly didn't match any of the 1000 other rocks from the basement excavation. 

Glacial erratics are transported by glaciers for hundreds and sometimes thousands of miles over a period of tens to hundreds of thousands of years. During that time they are literally "scrubbed" clean by constant contact friction with the snow and ice, in pretty much the same way that pebbles in streams or on the banks of the Great Lakes are scrubbed clean by moving water due to flow and/or wave action. In addition a glacier carries with it a good deal of other debris, some finer and some coarser, which over a period of say 20,000 years makes a lot of contact with many of the other things that flow with the glacier. Some rocks are carried along by the glacier and some get dropped, and they originate from many different places along the glacier's path. This explains the diversity. Google "glacial till in Illinois" and view the images.

[Rockwood]

6 hours ago, 4thgrdtcher said:

I didn't do any cleaning to this rock so no sand or silt was really attached to it. 

It looks like a relatively soft rock. The surface may slough away enough that soil does not adhere to it the way it does other rocks as they are dug up. 

Could be part of why it stands out.