MOOK, STUDY OF THE MORRISON FORMATION 177 



1888. 2. OsBOKN, H. F. : "On the structure and classification of the Mesozoic 

 mammalia." Phila. Acad. Nat. Sci., Journ., vol. ix, pp. 186-265, 30 figs., 2 

 pis., 1888. [Mammals from the Purbeck and Morrison formations de- 

 scribed and discussed, the Morrison forms being referred to as Jurassic] 



1889. 1. Hills, R. C. : [Address : The field for original work on the Rocky 

 Mountains.] Colo. Sci. Soc, Proc, vol. iii, pp. 148-164, 1889. [Suggests 

 collecting in the Atlantosaurus beds.] 



1889. 2. Stevenson, J. J. : "The Mesozoic rocks of southern Colorado and 

 northern New Mexico." Amer. Geol., vol. iii, pp. 391-397, 1889. [Jurassic 

 in southern Colorado consists of thin limestones; near Canon City shales.] 



1889. 3. White, C. A. : "The lower Cretaceous of the southwest and its re- 

 lation to the underlying and overlying formations." Amer. Journ. Sci., 

 3rd ser., vol. xxxviii, pp. 440-445, 1889. [Marine origin of the Dakota 

 shown by fossils. No Jura or Lower Cretaceous in central New Mexico. 

 No evidence of Triassic or Jurassic seas.] 



1890. 1. Ckagin, F. W. : "On the Cheyenne sandstone and Neocomian shales 

 of Kansas." Washburn Coll. Lab., Bull., vol. ii, pp. 69-80, 1890. Amer. 

 Geol., vol; vi, pp. 233-238 ; vol. vii, pp. 23-33, 1890. [The Cheyenne sand- 

 stone may be equivalent to the Atlantosaurus beds or to the Trinity series.] 



1890. 2. Hills, R. C. : "Additional notes on the eruptions of the Spanish 

 Peaks region." Colo. Sci. Soc, Proc, vol. iii, pp. 224-227, 1890. [Notes 

 the occurrence of Jurassic shales.] 



1890. 3. Emmons, S. F. : "Orographic movements in the Rocky Mountains." 

 Geol. Soc Amer., Bull., vol. i, pp. 245-286, 1890. [Atlantosaurus beds may 

 be Cretaceous. Term "Jura-Dakota" used. The beds are of fresh-water 

 origin. They were deposited around various "islands" in the Rocky Moun- 

 tain region.] 



1890. 4. Lakes, Arthur : "Extinct volcanoes in Colorado." Amer. Geol., 

 vol. V, pp. 38-43, 2 pis., 1890. [Notes cutting of Jurassic strata by vol- 

 canoes.] 



1890. 5. White, C. A. : "The North American Mesozoic" Amer. Assoc, for 

 the Adv. Sci., Proc, vol. xxxviii, pp. 205-226, 1890. [Atlantic Coast pos- 

 sesses upper Jurassic. The Potomac formation is divided. In "Interior 

 Region" a few hundred feet of Jurassic lie conformably on the Trias ; the 

 upper part is non-marine and lower part marine. Jurassic disappears 

 north and south, its distribution being less than that of the Trias.] 



1891. 1. Cannon, George B. : "Notes on the geology of Perry Park." Colo. 

 Sci. Soc, Proc, vol. iii, pp. 308-315, 1891. [Note on the Jura-Dakota hog- 

 back.] 



1891. 2. Marsh, O. C. : "Geological horizons as determined by vertebrate 

 fossils." Amer. Journ. Sci., 3rd ser., vol. xlii, p. 112, 1891 (abstract of 

 paper read to the Intern. Geol. Congr.). [The Hallopus beds are Jurassic 

 and older than the Baptanodon beds.] 



1891. 3. Crosby, W. O. : "On the contrast in color of the soils of high and 

 low latitudes." Amer. Geol., vol. viii, pp. 72-82, 1891. [Color contrast is 

 due partly to difference in climate under which deposits were formed and 

 also to geologic age.] 



1892. 1. Weed, W. H. : "Two Montana coal fields." Geol. Soc Amer., Bull., 

 vol. iii, pp. 301-330. 13 figs., 1S92. [Jurassic and Kootenie beds are both 

 present at Great Falls, Montana.] 



