H. H. Howorth — Coarse of the Rivers of Siberia. 5 



(4) The epoccipital bones. 



(5) The aborted transverse bone. 



These are all features not before seen in the Dinosauria, and show- 

 that the family is a very distinct one. 



The peculiar armature of the skull has a parallel in the genus 

 Phrynosoma, among the Lizards, and Meiolania, among the Turtles, 

 and it is of special interest to find it also represented in the 

 Dinosaurs, just before their extinction. 



Such a high specialization of the skull, resulting in its enormous 

 development, profoundly affected the rest of the skeleton. Precisely 

 as the heavy armature dominated the skull, so the huge head 

 gradually overbalanced the body, and must have led to its destruc- 

 tion. As the head increased in size to bear its armour, the neck 

 first of all. then the fore limbs, and later the whole skeleton, was 

 specially modified to support it. 



These features will be discussed in a later communication, but to 

 the present description of the skull should be added the fact that the 

 anterior cervical vertebras were firmly coossified with each other, 

 an important character not befoi'e observed in Dinosaurs. 



The skull represented on the accompanying Plate is the type 

 specimen of Triceratops flabellatns, Marsh. It was found in the 

 Ceratops beds of Wyoming by Mr. J. B. Hatcher, who also dis- 

 covered the type of the genus Ceratops, in the same horizon in 

 Montana. 



II. — Did the Great Eivers of Siberia Flow Southwards and 

 not Northwards in the Mammoth Age ? l 



By H. H. Howorth, Esq., M.P., etc. 



THE question proposed in the heading to this paper seems a 

 startling one. That the drainage of such a wide continental 

 area as Northern Asia should have been entirely reversed at such 

 a recent geological period as the Mammoth age, so that its present 

 great drains, the Ob, the Yenissei and the Lena, did not exist at all, 

 but their places were taken by other rivers pouring their waters, 

 not into the Arctic basin, but into some great Mediterranean Sea 

 in Central Asia, seems a paradox. It is nevertheless a conclusion 

 which has been forcing itself upon me for a considerable time, and 

 which I should like to be allowed to argue. 



To begin with the current movement of the land in Northern 

 Siberia, there can be no doubt whatever that the whole northern 

 seaboard of the continent is rising rapidly from the water. Erman, 

 Middendorff, and Wrangel, all diligent and careful explorers, are as 

 one in regard to their lesson, which is that the northern part of 

 Siberia, and, may I add, of Siberia in Europe also, that is to say, of 

 the whole continent from the White Sea to Berings Straits, is rising 

 from the sea. In a paper I wrote many years ago, which was pub- 

 lished in the Journal of the Geographical Society, on Eecent 



1 Full text of paper read in Section C (Geology) at the British Association, 

 Newcastle-upon-Tyne, September, 1889. 



