BIOGRAPHICAL SKETCH OF JOHN BELL HATCHER. XXI 



traveler and explorer. It will be noticed that the series embraces the Jurassic, the Cretaceous, 

 and the Tertiaries of western North America and of the extremity of South America. The reader 

 of these papers is impressed as much with the wealth of detail as with the power of generaliza- 

 tion and imagination of past geological conditions, which is especially manifested in his devel- 

 opment of the eolian v. the lake-basin theory of deposition' in the western Oligocene and 

 Miocene, in his discussion of the stratigraphic relations of the Judith River beds, in his discus- 

 sion of the geological history of Patagonia, and in his final geological paper, delivered at the 

 anniversary meeting of the Philosophical Society in 1904, "An attempt to correlate the marine 

 with the nonmarine formations of the Middle West." 



Fresh from his explorations for the Ceratopsia and Brontotheriidse were the first two papers 

 which came from his pen, "The Ceratops beds of Converse County," settling their Upper Cre- 

 taceous age, and "The Titanotherium beds," establishing the geological and stratigraphical 

 sequence of various species of titanotheres, as well as the thickness and subdivision of the 

 Titanotherium beds into three levels. In 1894 his "Note on the geology of northwestern 

 Nebraska ' ' contained the first of his observations on the relations of the Loup Fork and Equus 

 beds, which were continued during a number of years and were brought to a conclusion in 

 his remarkable paper of 1902, entitled "Origin of the Oligocene and Miocene deposits of the 

 Great Plains," in which he strongly combated the lake-basin theory and advocated the theory 

 of flood-plain and eolian deposition. 



The first fruits of the Princeton Patagonian Expedition was a short paper entitled "The 

 Cape Fairweather beds," in which he described this new marine horizon overling the Santa 

 Cruz deposits. These four years of exploration resulted in his entire rearrangement of the 

 Upper Cretaceous and Tertiary rocks of Patagonia, as set forth in his two papers "On the 

 geology of southern Patagonia" (November, 1897) and "Sedimentary rocks of southern Pata- 

 gonia" (February, 1900). The latter contains his final conclusions and is of very great impor- 

 tance. In this paper (1) he states that the Eocene was a period of depression, in which there 

 was no fresh-water deposition; (2) he removes the entire series of typical Patagonian beds 

 from the Eocene, where it was formerly placed, and refers it to late Oligocene and early Miocene; 

 (3) he states that the Pyrotherium beds, as that term has been used by Doctor Ameghino, 

 include a series of deposits of varying age from Eocene to Pleistocene — deposits of limited 

 area appearing on eroded surfaces of the Guaranitic Cretaceous beds, and thus producing the 

 confusion which has existed regarding the age of the Pyrotherium: fauna; (4) he states that the 

 Santa Cruz beds immediately and conformably overlie the Patagonian beds. 



