96 



CONTRIBUTIONS TO PAL^ONTOLOGY 



interbedded shales are also yellowish, and are soft and sandy, and non-concretion- 

 ary. The coal beds are generally thin but arc of better quaUty than the hgnites of 

 the Lance formation. The thickness of the "TuUock" formation in this region is 

 roughly estimated at about 400 feet. 



The beds above the "Tullock" were not examined in the Lance Creek area. 

 In the Gillette coal field Dobbin and Barnett divided these beds into the Lebo shale 

 member and the Tongue River member of the Fort Union "formation." ' 



The various units of the Fort Union group of the Lance Creek area and con- 

 tiguous arcas have yielded a considerable number of fossil plants. The foUowing 

 identified species were reported by Knowlton from the lower 200 feet of the Fort 

 Union "formation" of the region shown in figure 2: - 



Ampelopsis montanensis Cockerell 

 (Vitis cuspidata of Knowlton) 



Celastrus pterospermoides Ward 



Celastrus? taurinensis Ward 



(C. curvinervis of Knowlton) 



Cornus newberryi Hollick? 



(C. acuminata? of Knowlton) 



Diospyros brachysepala Al. Braun 



Grewia celastroides Ward 

 Grewia crenata (Unger) Hecr 

 Parottia cuneata (NewberrjO Berry 



(Viburnum cuneatum of Knowlton) 

 Platanus raynoldsii Newberry 

 Sequoia nordenskioldi Heer 

 Zizyphus serrulatus Ward 



Only 1 of these species, Celaslrusl taurinensis, is known also from the underlying 

 type Lance formation. Sequoia nordenskioldi is known elsewhere from beds of 

 Lance age, but is of no correlative significance, as it represents a type of conifer 

 foUage of extended stratigraphic range from the Upper Cretaceous into the Ceno- 

 zoic. Of the remaining 9 species, 5 are known elsewhere only in the type Fort 

 Union or other undoubted Paleocene beds, and the remaining 4 species are known 

 only in beds of Paleocene and Eocene age. This analysis leaves Uttle doubt as to 

 the Paleocene age of the beds. 



During the summcr of 1938 I coUected, on the basis of information received 

 from Dr. William W. Rubey, of the U. S. Geological Survey,^ a number of fossil 

 plants from thc lowcr 100 feet of the TuUock formation of the Gillette coal field area. 

 These were obtained from an old coal prospect on Coal Draw, 11 miles south by east 



of Moorcroft, Wyoming, SE. 

 have been identified: 



sec. 28, T. 48 N., R. 67 W. The following species 



Ancimia lanccolata Knowlton 

 Celastrus? taurinensis Ward 

 Glyptostrobus dakotensis Brown 

 Hicoria antiquora (Newbcrry) Knowlton 

 Onoclea sensibiUs fossiiis Newberry 



Platanus coloradensis Knowlton 

 Sapindus afFmis Newberry 

 Sequoia nordenskioldi Hcer 

 Thuja intcrrupta Newbcrry 



In this assemblage, the 2 species which occur also in the type Lance or equiva- 

 lent beds {Celastrus? taurinensis and Sequoia nordenskioldi) are elsewhcre known to 

 extcnd from late Cretaceous into Paleocene time and were discusscd above. Of the 

 remaining 7 species, 5 are known definitely onlj^ in undoubted Paleocene beds, and 



'Ibid.,9-n. 



' SlQnton, T. W., and Knowlton, F. H., op. cit., 134-136, 1897. 



' Writtcn communication, May 11, 1936. 



