THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE III. VOL. VIII. 



No. v.— MAY, 1891. 



GlRXG-XlSTJ^Xj .A^iaTIGXiES. 



I. — The Gigantic Ceratopsid^, or Horned Dinosaurs, op 



North America.^ 



(PART II.) 



Ey Prof. 0. C. Marsh, Ph.D., LL.D., F.G.S., etc. 



(PLATES IV. 2 AND V.) 



TWO years ago at the Bath Meeting of the British Association, I 

 had the honour to present a paper in which I compared the 

 principal known Dinosaurs of Europe with those of America.^ In 

 this communication I referred to some peculiar reptilian remains 

 from the Gosau formation of Austria, and compai'ed them with 

 certain Laramie fossils from America, about whicli I hoped soon to 

 have more definite information. As an indication of the rapidity 

 with which knowledge of ancient life is advancing, it may be 

 interesting 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 tlie Ceralopsidce, and I shall refer 

 especially to the forms I have recently investigated, and hope to 

 describe more fully later on, under the auspices of the United States 

 Geological Survey. 



The geological horizon of the Geratopsidce 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 Eocky Mountains. It 

 is marked almost everywhere by remains of these reptiles ; 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. 



The fossils associated with the Cernlopsidce are mainly Dinosaurs, 

 representing two or three orders, and several families. Piesiosaurs, 

 Crocodiles, and Turtles of Cretaceous types, and many smaller 

 reptiles, have left their remains in the same deposits. Numerous 

 small mammals, also of ancient types, a few birds, and many fishes, 



1 Read before Section C of the British Association for the Advancement of Science, 

 at the Leeds Meeting, September 4, 1890. See also American Journal of Science (3), 

 vol. sxxvi. p. 477, December, 1888 ; vol. xsxvii. 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. - For Plate IV. see the April Number Geol. Mag. 



^ Report of the British Association for the Advancement of Science for 18S8, 

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

 April, 1889. See also Geol. Mag. 1890, pp. 1-5, and PI. I. 



DECADE III. — VOL. VIII. NO. T. 13 



