including land managers of our federal lands, our congress, and state congressional delegations, for example. the public, nongovernmental organizations. and as well as industry. so let me step back just a little bit so we understand what an unconventional resource a little bit better. this diagram is sort of a cartoon, cross section to the earth. conventional oil and gas resources occur in pools or reservoirs that are constrained on the top and on the sides by impermeable zones. and they often have an oil/water contact or gas/water contact. and unconventional resources, we technically refer to them as con tenuous resources because the oil resource or gas resources is distributed con tenuously through the formation at depth. and the rock is so impermeable or tight and that's why we need to use techniques such as hydro fracking and horizontal drilling to extract the resource. one example of the resource assessment is our recently completed marcellus shale gas assessment in the northeastern united states. being from this area, you probably heard of it, or maybe not. but at the bottom, i list here what our mean estimate, which was 84 trillion cubic feet of gas.