Yup, at least that was my first thought. I could be wrong though. From the way you described your splitting experience I thought immediately it was pine too. Green, knotty pine can sometimes be like trying to split a rubber tire. The smell is another good way to tell if it’s pine. Very distinctive. I love the smell of fresh cut pine. I am surrounded by huge ponderosa pine forests so I get lots of that stuff. Not “all nighter” firewood but lots of heat and great shoulder season wood or for when you want a fire that is shorter in time. Burns very hot and not lots of ash comparatively speaking. Burn it green and it will burn great because the pitch burns like rocket fuel but it will create dangerous creosote. Season it one year or more cut and split and you are good to go.
He IS GOOD for sure, trust me, i'm a walking, talking example of how good he is. He saved my life several times over, honestly. I'm far from perfect, but, no doubt, he keeps me in line. I owe him every thing!!
Very good chance it is some kind of pine, there is some around here, and at one time, it was a pretty dominant tree in this area many, many years ago. Now some of the big company's are replanting pine back in some area's and even some good stands of cedar.