Spotting

Holes with radius 0.25mm to 1mm. Distance between holes vary 1-1.5mm. The tunnels go fairly straight downward, but its difficult to visualize an entire tunnel. Found in pile of excavated stone from the lakes formation. They dug the lake as a flood management project through the Sac River. In short, the rock was dug from an old river bed to make room for a lake. I looked for any other rock that had the same markings and found none.

How big are these holes, and how deep? This looks like the result of some kind of boring mollusc. There are many kinds of bivalves that bore through stone like this and make these kinds of "swiss cheese" rocks, the most common group being the Pholads. They make very small holes, some only a centimeter in diameter. I'm not 100% clear on where you found this... You collected it in a river or lake? That would really help!

well...me neither. But I can't explain what else could have caused fairly symmetrical openings straight through a piece of rock..

I study geology and i'm not convinced its a fossil! Sorry!

It might help to have some more information for this. Some questions I can think of... what is the base stone like? hard? soft? calciferous? fractured? heated? Do the holes have any direction to them? if so maybe gravity relevant... how deep are the holes? do they have any form inside or are they smooth? .... Can you find any 'half' holes or are they all the same depth? ...Go on - be a detective :)

I think, now that Ive researched this for 20hours, I've come up with a possible ID: PALM? I read where the midwest actually has several petrified wood or petrified palm species. IDK...And I haven't been able to get one fossil expert to give me a clue...I like it and it makes a cool conversation piece.