I think water hickory looks very close, but I read those need very wet media, almost bogish. I doubt that happens here. So Arizona walnut is the closest so far I think. I found the exact location, here is a google street level mapping of it. Maybe these further pics will help too.
<iframe width="425" height="350" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="http://maps.google.com/maps?f=q&source=embed&hl=en&q=Coolidge,+Pinal,+Arizona&sll=37.0625,-95.677068&sspn=44.793449,91.669922&ie=UTF8&cd=1&geocode=Fa8z9wEdSGBa-Q&split=0&hq=&hnear=Coolidge,+Pinal,+Arizona&ll=32.977839,-111.517624&spn=0.001464,0.002798&t=h&z=14&layer=c&cbll=33.025221,-111.38753&panoid=KfQsv8SEqwiovIEFyLgTUQ&cbp=12,254.81,,0,3.36&output=svembed"></iframe><br /><small><a href="http://maps.google.com/maps?f=q&source=embed&hl=en&q=Coolidge,+Pinal,+Arizona&sll=37.0625,-95.677068&sspn=44.793449,91.669922&ie=UTF8&cd=1&geocode=Fa8z9wEdSGBa-Q&split=0&hq=&hnear=Coolidge,+Pinal,+Arizona&ll=32.977839,-111.517624&spn=0.001464,0.002798&t=h&z=14&layer=c&cbll=33.025221,-111.38753&panoid=KfQsv8SEqwiovIEFyLgTUQ&cbp=12,254.81,,0,3.36" style="color:#0000FF;text-align:left">View Larger Map</a></small>