Hello all, it's been a very long time and I'm posting from my phone in an area with no wifi, so I hope I've followed all the rules as best I can.
I was out fossil hunting in the Upper Hell Creek in eastern Montana last year, and found this bone. (Sorry for the images, I will not be able to retake them for months.) It was found in a sandy mudstone and appears to be hollow (and very crumbly). Its about 10 inches long.My best guess is a Struthiomimus femur, but if anyone knows different please let me know. Thank you for any help you can give!