Kansas, Oklahoma, New Mexico and Texas. 199 



reader with too many details, I shall speak only of the Trinity 

 formation, of the locality in Pike County, Arkansas, close to 

 the boundary line of Texas. Mr. Hill, the inventor of the 

 name Trinity formation, has published in the Annual Report 

 of the Geological Survey of Arkansas, for 1888, vol. ii, Meso- 

 zoic, two chapters, xii and xiii, in which are described the strata 

 and the fossils, the latter with figures. It is useless to reprint 

 what I have said on each species of fossil ; I need only say, 

 that I have shown with accuracy and details, in the American 

 Geologist, Dec, 1889, pp. 357-367, that the whole fauna, with- 

 out a single exception, is composed of Jurassic fossils, and con- 

 cluded that instead of being Lower Cretaceous, the strata near 

 Murfreesboro represent in Arkansas and Texas the superior 

 Jura from the Oxfordian upward, including the Purbeck 

 formation. 



As an example of carelessness, not to use a stronger word, 

 in quoting a plain paleontological fact, I call the attention of 

 the reader to a quotation of Mr. Hill, at p. 128. In the 

 description of Ammonites Walcottii, we read : "It resembles 

 . . . also Ammonites Yo, d'Orb. of the Lower Cretaceous." 

 Turning to the great work of the Paleontologie Franqaise by 

 d'Orbigny, in order to examine and verify the resemblance of 

 the two Ammonites, I naturally took up the volumes entitled : 

 "Terrain Cretace." But there is no trace of Ammonites Yo 

 in those volumes. As I know the species well and that the 

 form is undoubtedly Jurassic, I took the volumes entitled : 

 " Terrain Jurassique," and there in vol. i, pp. 545-516, is the 

 Ammonites Yo with the special location of "Etage Kimmerid- 

 gien, Boulogne -sur-Mer." Instead of belonging to the Lower 

 Cretaceous, according to the extraordinary alteration of Mr. 

 Hill, it is an Upper Jura species. Why Mr. Hill took upon 

 himself to change the age of the Ammonites Yo, cannot be 

 explained otherwise, than that he wanted to sustain his classi- 

 fication of the Trinity division in the Cretaceous, quoting in 

 his favour the great authority of d'Orbigny. This case shows 

 how unreliable Mr. Hill is, when he writes on paleontology. 



Kansas. — As long ago as 1888, I corresponded with Profes- 

 sor F. W. Cragin of Topeka, in regard to a Cycadoidea found 

 in Maryland, for the purpose of comparing it with a specimen 

 of the same genus of fossil plant collected in Kansas. On 

 reading Professor Cragin's first two papers on the geology of 

 a part of southern Kansas comprising Barber, Pratt, Kiowa and 

 Comanche counties, south of the Arkansas River, in the upper 

 region of Medicine Lodge River, I thought that the Jura 

 existed there, and wrote so to him. He sent me a small box 

 of specimens, all Cretaceous fossils. After an exchange of a 

 few letters on the subject, the correspondence was dropped. 



