Do you remember when we were hiking near those glaciers at the Atigun Pass, in the Gates of the Arctic National Park?  We saw that glacier that had till along the side where the glacier met the the valley wall.  That lateral moraine formed when rocks fell from the valley wall onto the glacier. The till eventually drops along the side of the glacier as it melts.  

When two glaciers run into one another, their lateral moraine smush together to form one row of till along the center point where the two glaciers came together.  We saw this at Wrangell St. Elias National Park.

Remember back at Exit Glacier, we saw that pile of small rocks and dirt out in front of the glacier?  That was the Terminal Moraine.  As the glacier moves forward, it pushes rocks ahead of it like a bulldozer.  When the glacier stops moving forward for a bit and then begins to recede, it will drop a lot of the till that was trapped in the ice.  Together, these two deposits create a long pile of till along the front (cross-valley) of the glacier.  The Terminal Moraine is a great clue to find out how far forward a glacier pushed before it started receding.