My initial thought is that it is simply a naturefact.  I know the crossing lines look intentional, but I have seen "incising" that results from natural processes before - including roots cutting into soft stone, natural crystalline/weatehring differences etc.  I would suggest getting it to a local geologist that could tell you more about the stone itself (is it argillite?  I know that weather in strange ways but do not have much personal experience with it). 

  as for c14 labs - I have usually worked with Beta-Analytic, but there is a large listing of labs to check into at http://www.radiocarbon.org/Info/ .  What do you have that might be datable - since the pictured item seems to be stone - it can not be for that.

Good Luck with your efforts.

Looks too symetrical to be naturefact; two well executed X's, etc.  I take it this is wood?  If so, any petrification to it?   

Thank you for the comments.  The variety of opinions is educational.  I had never considered that it might be a geofact or naturefact.  The area where it was found is an argillite reduction quarry in which large masses of exposed bedrock were  hammered into smaller workable pieces which were then reduced into a variety of tools or tool blanks to be traded.  Except for the hammerstones and some jasper pieces every rock is argillite and could be called artifactual although debitage, waste and substandard blanks are not the artifacts that come to mind as interesting.  This piece is argillite, 4.5 lbs of it
I am planning to excavate a large rock pile on the property.  There may be something dateable in that pile so I want to know about labs in advance.  Thank you Dmack89 for the link.

Since you were seeking C14 labs, I thought the item to be of wood.  The lines IMO  appear to be man made.  Especially if they wrap around.  Possible that they might have formed due to being tied to something and the ties were stressed and shifted frequently grinding on the rock.  Might be a weight tied to a net or machinery from 18th or 19th century???

Looks natural to me too.

I spoke with a colleague this morning that has done a great deal of work in the NJ/PA area where argillite is abundant.  He took a look at the images put forth another possible cause - Plow and/or disc scars.  Initially I was skeptical of this since the lines seem to be so narrow and well defined, and I have seen many plow scared rocks - but the lines are not nearly this well define.  However he pointed out that as argillite weathers, it becomes a very soft stone, easily cut.  As I considered that it began to make more sense.  Also, if you consider the incisions not as paired  X s but rather as parllel lines cut in different directions, I can see how multiple strikes of a stone by discing - either in one season or over several if the stone is just at the bottom of disc depth, could easily result in this pattern. 

The important question to ask when considering this possibility - has the location of the find ever been a plowed field?

Discing can wreck havoc on artifacts as well as "create" some.  What makes me suspicious that this is not a disc type naturefact is that Dmack89 says the X's are continuous across the back.  The probabiility of disc generated lines being continuous on both sides and with no apparent chipping is IMO rather low.  Granted, argillite is often soft, but these lines do look a bit crisp and not the least bit rounded out or wallowed out in their cuts as one would expect from a disc cut on a stone this size.  Wish we all had the 3D technology to  "print" such items for personal viewing/handling! 

The incisions are indeed continuous.  Near the tang or the bottom of the Lithic are another set of parallel lines not crossing, but also wrapping around.  The location where it was found could have been a cultivated site both historic and prehistoric.  Not quite a plowed field, but rather a planted plot.