Educators especially: I encourage you to use anything you find here that is useful to your mission educating people about Earth science. E-mail me if it would help to have a larger or higher-resolution version of any of the images.
If you can get into NJ, assuming you have a car, you will love the columnar jointing in the Orange Mountain Basalt in the roadcuts along Interstate 280, which I think is called the Orange Mountain Expressway. I saw it back in the 1980′s and it was spectacular. I have a couple of photos here: http://facstaff.gpc.edu/~pgore/geology/geo101/plutons.php
Along Interstate 280:
Driving westward along Interstate 280 the highway crosses the valley west of Newark … the highway begins to ascend the grade rising to the ridge top of the 1st Watchung (Orange Mountain) … The cliffs consist of a single massive lava flow that cooled and cracked into columnar joints. The unusual feature of this flow are the complexity of the columnar joints. In some locations, the joints tend to radiate away from a central core. These patterns were generated by an uneven cooling pattern in the flow, possibly a result of degassing structures or uneven mixing of the lava as it cooled.