Giant ammonites cause planes of weakness inside the concretions, and yearly freezing and thawing cycles cause cracks to form along these planes. All this makes the excavation process easier; a gentle tap with the crowbar is often all it takes to split apart the concretion and lift off the top like a manhole cover. But these ammonites are heavy, and getting them out of the ground is no small job. When the ammonite doesn't easily separate from the lower half of the concretion, the DMNS crew must pry up the entire nodule with crowbars.
In the August 1998 dig, Kirk Johnson, Emmett Evanoff, and Ray Troll were able to collect a dozen of these spectacular fossils. The DMNS crew carried the precious cargo to Big Blue, the Museum's premier fossil-collecting truck, and returned them to the Museum.