110 KA2fSAS Academy of Science. 



marked difference between the upper and the lower beds, in the relative amount and 

 in the kinds of fossil remains. In the very lowest, the exposures are exceedingly 

 barren in vertebrate fossils. A day's search will not reveal a half dozen specimens 

 of any kind. In one day last year, the three members of my party found over SO 

 saurians, five or six pterodactyls, several turtles, and fishes innumerable, in the upper 

 beds. On the other hand, the invertebrates are here especially numerous, strewing 

 the surface in heaps; large and perfect Haploscaphas, Rudistes, etc., can be obtained 

 literally by the wagon load, while, for the most of them, one would search the upper 

 beds in vain. I have never known any reptilian remains to be found within lUO 

 feet of the base, though, in all probability, some species do occur here. As we go 

 upward, the vertebrates become more abundant, and the invertebrates, save the 

 ostrea and the large, thin-shelled, four-foot inoceramid, and perhaps some others,, 

 become markedly less numerous. Among the vertebrates, two of the three genera of 

 the mosasaurs occur throughout, but the third, Clidastes, I have never known to b» 

 found save in the upper part. The plesiosaurs are rare everywhere, but relatively 

 more abundant in the lower strata. Of the pterodactyls, the larger species are rela- 

 tively more abundant below, though absolutely more numerous above. Finally, the 

 turtles are exceedingly rare in the lower parts, but are very commonly met with in 

 the uppermost strata. With two possible exceptions, the birds have never been 

 found below the yellow chalk. This all seems to show that the water gradually be- 

 came more shallow, and the shore lines less remote, as the formation grew younger. 



The horizon of the yellow chalk can be readily traced, from near Monument 

 Rocks on the south, northeastward to the Saline, north of Wa Keeney, and thence ta 

 the South Fork of the Solomon, near Hill City. It occurs on the North Fork of the 

 Solomon, east of Lenora, but how much further east I cannot say. Some small out- 

 crops, apparently of the same, I have observed on the Prairie Dog, near Norton. 



It wiU be seen from the foregoing that I admit of no stratigraphical distinction be- 

 tween chalk and blue shale. The difference between these is whoUy chemical, and has 

 nothing to do with the geological position. I may add that the rare crinoid, Uiuta- 

 crinus, which was originally described from Kansas specimens, seems to be confined 

 to one horizon, near the middle of the beds. A large and magnificent slab or plate 

 of these interesting fossils, covering fuUy 20 square feet, was obtained by our party 

 the past year from the Smoky Hill, near Elkader, and now is one of the treasures of 

 the State University museum. 



Some years ago, Professor Mudge discovered, near the old town of Sheridan, a 

 large mass of baculite. On referring specimens of them to the veteran paleontol- 

 ogist, the late Professor Meek, the species was determined as Baculites anceps, with 

 the following remarks, as published by Professor Mudge: "One fact in regard to 

 your specimens, however, is very curious to me. All the other forms like this that 

 I have ever seen from any part of the far West come from Nos. 4 or .5, while all of 

 the species yet known from these upper rocks are distinct from anything found in 

 Nos. 2 or 3. Can it be possible that you might have found this in anoutlier of Nos. 4 

 or 5? It has the shell substance well preserved, like the fossils of these upper beds, 

 while those in the lower beds are usually casts." Mudge, however, thought that the 

 deposit was clearly Niobrara. 



I believe that Meek was right, and that the beds here represented are eithtr of 

 the Fort Pierre group, or transition beds to that group. My reasons are as follows: 

 Not another specimen, so far as I know, of this baculite or of any other has ever 

 been found below this horizon. Furthermore, in a visit to the locality the past year, 

 a careful search did not reveal any other invertebrates known from the chalk below 

 it, but did disclose one or two other moUusks that I have never seen elsewhere in all 

 the years I have spent in this formation. I have not yet had an opportunity to de- 



