HISTORICAL REVIEW OF THE LARAMIE PROBLEM. 



27 



The statement that "a distinct horizon" has been 

 ''traced nearly 800 niiles" and that "it is marked every- 

 where" by certain fossils would imply either that actual 

 continuity had been proved or that the stratigraphic 

 position of the fossil-bearing strata had been found to be 

 clearly the same at numerous localities not far apart. 

 But when Prof. Marsh made the above assertion the 

 Denver eegion was the only one in which the position of 

 the Ccrafops-bearing beds had been established in complete 

 sections, and here they were found to be separated from 

 the typical Laramie below them by a great stratigraphic 

 break. Moreover, none of the described fossils was found 

 east of the mountains between the Denver Basin and 

 Converse County, Wyo., a distance of 200 miles. As far, 

 then, as the new fossils themselves are concerned, they 

 prove either a great extension of the Arapahoe and Denver 

 (post- Laramie of this report), or a distribution of the fossils 

 in question beyond the limits of what may be properly 

 termed one formation or horizon. 



In the following paragraph Cross added : 



In the original description by Prof. Marsh the fossils 

 were said to have been obtained in "the Laramie of 

 Wyoming" or "the Ceratops beds of Wyoming." It is 

 important to emphasize the fact that not one of the de- 

 scribed s])ecies came from the ty])ical Laramie strata of 

 southern Wyoming or from their demonstrated equivalent. 



In succeeding years Marsh "* continued to 

 publish short papers on the Converse County 

 material, but without a definite indication of 

 locality, the only statement being that the 

 fossils were "from the Laramie" or "from the 

 Ceratops beds of Wyoming." In February, 

 1893, however. Hatcher"^ published a short 

 paper, in which, for the first time, complete 

 and definite information was given as to the 

 localitj' at which this wonderful vertebrate 

 fauna had been found, as well as a description 

 of the lithologic character and stratigraphic 

 occurrence of the beds containing it, and also 

 the reasons for regarding the horizon as refer- 

 able to the true Laramie. 



The typical area for the " Ceratops beds," 

 which have since become classic, was stated to 

 be in the northeastern portion of Converse 

 County, now included in Niobrara County, 

 which lies on the eastern border of Wyoming. 

 These beds were also found in adjacent portions 

 of Weston County. In his description of the 

 deposits Hatcher said : 



« Marsh, O. C, Additional characters of the Ceratopsidae, with notice 

 of new Cretaceous dinosaifrs: Am. Jour. Sci., 3d ser., vol. 39, p. 418, 

 1S90; The gigantic Ceratopsidae, or horned dinosaurs of North America: 

 Idem, vol. 41, p. 167, 1891. 



»» Hatcher, J. B., The Ceratops beds of Converse County, Wyo.: Am. 

 Jour. Sci., 3d ser., vol. 45, pp. 135-144, 1893. 



The Ceratops beds are made up of alternating sandstones, 

 shales, and lignites, with occasional local deposits of lime- 

 stones and marls. The different strata of the series are 

 not always continuous, a stratum of sandstone giving place 

 to one of shales, and vice versa. This is generally true of 

 the upper two thirds of the beds. * * * The shales 

 are quite soft and loosely com])acted, composed mostly 

 of clay with more or less sand in places. The prevailing 

 color is dark brown, but they are sometimes red or bluish. 

 * * * The lignites occur in thin seams, ne^er more 

 than a few inches thick, of only limited extent, and with 

 many impurities. * * * All the deposits of the "Cera- 

 tops beds" of this region bear evidence of having been 

 laid down in fresh waters. Among the invertebrate 

 fossils found in them, only fresh-water forms are known. 

 There is no evidence that marine or brackish waters have 

 e\er had access to this region since the recession of the 

 former at the close of the Fox Hills period. 



As regards the stratigraphic position of the 

 " Ceratops beds," Hatcher stated that the 

 lowest exposed member of the section was 

 identified by its numerous invertebrates as 

 Pierre. Overlying this was an alternating 

 series of sandstones and shales having an esti- 

 mated thickness of 500 feet and containing, 

 especially in the upper portion, an abundant 

 invertebrate fauna juonounced to be t3'])ically 

 Fox Hills. Above this series came the " Cera- 

 tops beds," which had an estimated thickness 

 of 3,000 feet. He added: 



All the beds of the entire section are conformable and 

 bear evidence of a continuous deposition, from the Fort 

 Pierre shales up through the Fox Hills sandstones and 

 overlying fresh-water Ceratops beds. The Fort Pierre 

 shales are not suddenly replaced by the Fox Hills sand- 

 stones, but the transition is a gradual one, and it is impos- 

 sible to say just where the one ends and the other begins. 

 The same is true of the beds overlying the Fox Hills. The 

 thin seam of hard sandstone, separating the fossil-bearing 

 Fox Hills sandstones below from the very similar non- 

 fossiliferous sandstone above, is here regarded as the 

 dividing line between the Fox Hills and the Ceratops 

 beds. But this decision, it must be admitted, is quite 

 arbitrary, and the evidence in its favor is negative rather 

 than positive. The only reason for placing the overlying 

 400 feet of nonfossiliferous sandstones in the fresh-water 

 series is the absence of fossils in them. 



In discussing the age of the "Ceratops beds" 

 Hatcher said : 



Owing to the fact that very few vertebrates had pre- 

 viously been described from the tji^ical Laramie, aa first 

 defined by Mr. Clarence King, and the consequent lack of 

 vertebrate forms known to have come from the Laramie 

 for comparison with those found in the Ceratops beds, it 

 must be admitted that the vertebrate fauna of the latter is, 

 in itself, at present not sufficient proof to establish the 

 Laramie age of the Ceratops beds. 



