Opinions Wanted - Casting Or A Crack In Block (pic)

Machine shop showed me this after magnafluxing and they are not 100% sure if this is a casting flaw or a crack. Seems like casting to me because it is raised. What do you think?
 

Attachments

  • 20160502_171704.webp
    20160502_171704.webp
    70.3 KB · Views: 208