APPENDIX. 



Art. XIX. — The gigantic Ceratopsidce, or horned Dinosaurs, 

 of North America;* by O. C. Marsh. (With Plates I-X.) 



Two years ago, at the Bath meeting of the Association, 

 I had the honor to present to this section a paper in which I 

 compared the principal known Dinosaurs of Europe with those 

 of America.f In this communication, I referred to some 

 peculiar reptilian remains from the Gosau formation of Austria, 

 and compared them with certain Laramie fossils from America, 

 about which I hoped soon to have more definite information. 

 As an indication of the rapidity with which knowledge of 

 ancient life is advancing, it may interest you to know what 

 has been learned, in two years, concerning this single group of 

 the remarkable reptiles known as Dinosauria. This group, I 

 have termed the Ceratopsidce, and I shall speak especially of 

 the forms I have recently investigated, and hope to describe 

 more fully later, under the auspices of the "United States 

 Geological Survey. 



The geological horizon of the Ceratopsidce, in America, is a 

 distinct one in the upper Cretaceous, and has now been traced 

 nearly eight hundred miles along the eastern flank of the 

 Rocky Mountains. It is marked almost everywhere by 

 remains of these reptiles, and hence I have called the strata 

 containing them, the Ceratops beds. They are fresh-water or 

 brackish deposits, which form a part of the so-called Laramie, 

 but are below the uppermost beds referred to that group. 



* Read before Section C of the British Association for the Advancement of 

 Science, at the Leeds meeting, September 4, 1890. See also this Journal (3), vol. 

 xxxvi, p. 417, December, 1888; vol. xxxvii, p. 334, April, 1889; vol. xxxviii, p. 

 173, August, 1889, p. 501, December, 1889; and vol. xxxix, p. 81, January, 1890, 

 p. 418, May, 1890. 



f Report of the British Association for the Advancement of Science for 1888, 

 p. 660. London, 1889. Abstract, this Journal (3), vol. xxxvii. p. 323, April, 1889.. 



