Need more info. Pics of leaves would help. You could look on the 'net at general photos of what different tree crowns look like. However, know that the same tree will likely have a different shaped crown depending upon whether it grows in a stand or in the open. Based on my experience you could have some oaks in there. Being as far north as you are, you could also have some Sugar Maple in the mix. Collect some old leaves and post pics if you can.