Near-surface geophysics (NSG) was not specifically addressed in the first edition of the Treatise on Geophysics. The decision to include a new volume in the second edition of the Treatise on Geophysics on the near surface reflects the ever-growing contribution that geophysics is making to our understanding of the outermost shell of the Earth. This growth is evidenced by the formation of a new focus group in NSG within the American Geophysical Union, the largest Earth science organization worldwide, in 2006 (Figure 1). The near surface is perhaps a somewhat nebulous term that means different things to different people.

The aim of the Treatise on Invertebrate Paleontology, as originally conceived and consistently pursued, is to present the most comprehensive and authoritative, yet compact statement of knowledge concerning invertebrate fossil groups that can be formulated by collaboration of competent specialists in seeking to organize what has been learned of this subject up to the mid-point of the present century.

The aim of the Treatise on Invertebrate Paleontology, as originally conceived and consistendy pursued, is to present the most comprehensive and authoritative, yet compact statement of knowledge concerning invertebrate fossil groups that can be formulated by collaboration oLcompetent special- „ ists in seeking to organize what has been learned of this subject up to the mid-point of the present century.

Cretaceous ammonites belong to the four suborders Phylloceratina, Lytoceratina, Ammonitina, and Ancyloceratina. The longranging Phylloceratina extend from low in the Triassic to the top of the Cretaceous, and those that occur in the Cretaceous belong to genera that originated in the Jurassic or are closely related to them.