946 



SCIENCE. 



[N. S. Vol. IV. No. 104. 



and the Lower Cretaceous, or Neocomian, so 

 well developed in Texas (Comet Creek, Fort 

 Washita, Comanche, etc.), is completely ig- 

 nored. By contra, Prof. Marsh places the 

 Laramie series in the Cretaceous. As he says, 

 "that vertebrates afford the most reliable evi- 

 dence of climate and other geological changes," 

 it is somewhat surprising to see him put aside 

 the beautiful discovery of an important and 

 rather rich vertebrate fauna near Eeims, in 

 France, by M. le Docteur V. Lemoine, at Cer- 

 nay and Ai, or Ay, in Champagne, absolutely 

 identical as regards the forms and genera with 

 what Prof. Marsh has imprudently called *a 

 Cretaceous Mammalian fauna ' in the Laramie 

 formation, showing 'how difficult it is to lay 

 aside preconceived opinions,' according to his 

 own phraseology. The Cernayrian fauna, as it 

 is called by Dr. Lemoine and Prof. Gaudry, is 

 Tertiary * and not Cretaceous. 



The stratigraphic position of the first mam- 

 mal Dromatherium in the Trias, according to 

 Fig. 1 of Prof. Marsh's paper, is contrary to the 

 opinion of the discoverer, Dr. E. Emmons, who 

 has always referred it to the Permian, for he 

 finds it far below the true Trias of North Caro- 

 lina and Virginia. 



Prof. Marsh insists on the variety of colors in 

 the plastic clays of the Jura at Gay Head, in 

 the Maryland, Wyoming and Colorado, saying: 

 " Brilliant red, green and yellow tints are es- 

 pecially prominent, yet the white and black 

 shades are equally noticeable" (Science, p. 

 812). This is very true and I saw the same 

 striking colors in New Mexico, calling atten- 

 tion, as far back as 1853, to the colors of 

 the sandstone with a remarkable yellow-citron 

 tint and the brilliant white of other beds of 

 sandstone at Tucumcari, Canon Blanco and 

 Laguna Colorado, and the blue of the Gryphea 

 Tucumcarii marls at Pyramid Mount. 



* Science, p. 835, in * Scientific Notes and News, ' 

 we read that Dr. Lemoine has exhibited photographs 

 obtained by Eontgen's rays, of fossils embedded in 

 the chalk strata of Eeims. The error of calling the 

 strata near Eeims, at Cernay and Ai in which Dr. 

 Lemoine has collected fossil bones of mammals, birds 

 and reptiles is difficult to understand, for he called 

 them, not chalk, but Tertiary or Lower Eocene {Bull. 

 8oc. G^ol. France, 1 Nov., 1896, pp. cxciii-cxcv). 



In regard to early investigations, Prof. Marsh 

 has the kindness to recall my contribution of 

 1853 in the Eocky Mountain region, when I 

 found the Jura at the Tucumcari Mounts,^ 

 Canon Blanco, Laguna Colorado, and in the 

 vicinity of Zuni (New Mexico and Arizona), in 

 1853, the Jurassic formation had not been truly 

 recognized yet in North America, for the only 

 indication of Prof. W. B. Eogers of the Oolitic 

 age for the coal of the vicinity of Eichmond^ 

 Virginia, was proved as early as 1849, as be- 

 longing truly to the Trias and not to the 

 Jura. 



Prof. Phillip T. Tyson, of Baltimore, after re- 

 ferring the red plastic clay of Maryland first to- 

 the Cretaceous in 1860, changed his view in find- 

 ing specimens of Cycadea, and in 1862 called it 

 Jurassic. In 1863 I saw the same formation 

 in the vicinity of Washington and did not hesi- 

 tate to call it Jurassic ; but I published nothing 

 about it, until 1888, in my paper ' American, 

 classification and nomenclature,' pp. 36-37, 

 Cambridge, saying : ' ' During the Civil War 

 (November, 1863), when visiting some friends 

 in camp around Washington, I was shown a 

 fossil ' pineapple ' found on the farm of Dr. 

 Jenkins, one mile south of the Baltimore and 

 Washington railroad, sixteen miles from Wash- 

 ington, Prince George County, Maryland. I 

 recognized at once a well preserved Purbeck's 

 Cycadea and referred the red and gray mark, in 

 which it was found in company with pieces of 

 petrified wood and broken pieces of indetermi- 

 nable bones, to the Purbeck formation of Eng- 

 land, The little of what I saw there reminds 

 me of the Purbeck group, as I saw it at Port- 

 land Island and Durlstone Bay, near Weymouth^ 

 England, where so many specimens of mam- 

 malia (marsupial), reptiles, birds, turtles, fishes 

 and Cycadea have been found in its celebrated 

 ' dirt bed.' 



' ' Lately the United States Geological Survey 

 have called those white, red and bluish gray 

 clays and sands Potomac formation. It is a fresh 

 water deposit contemporaneous with the Pur- 

 beck strata of Swanage and vicinity, Dorset- 

 shire, England, which represent in North 

 America that most important upper part of the 

 Jurassic system called now on the continent of 

 Europe the Purheckian. ' ' So the Potomac for- 



