448 >S'. AUport — Relative Ages of Igneous Rocks. 



I have already given reasons for believing the nose of Sivatherium 

 resembled that of Saiga, and remotely the Elk, and was therefore not 

 prehensile. Comparing the same forms, there seems no reason why 

 the digestive organs should not have been as complex as in them and 

 other horned ruminants, and the act of rumination also corresponding. 

 I believe the body to have been quite as bulky as that of cattle and 

 deer, and much more so than in the ordinary antelope group. My 

 conception of the animal I depict and the features tell their own 

 tale, to wit, a creature with several herbivorous traits combined. 



I might surmise more regarding this strange animal, and conjure 

 a picture ^ rivalling modern Eastern tales ; but with imperfect data 

 haziness, like distance, lends enchantment to the view. 



EXPLANATION OF PLATE XII. 



Eestoration of the skeleton of the Sivatherium giganteum, Falc. and Cant. 

 This is based on the remains deposited in the British Museum, and partly on Dr. 

 Falconer's figures and descriptions of the several fragments in the Calcutta Museum 

 and elsewhere. 



The under-mentioned bones, and portions of bones, are separately illustrated in the 

 published and unpublished parts of the " Fauna Sivalensis." 

 Cranium cf and $ diiferent views. 

 Several portions of the horns. 

 Cervical vertebrae separate and in situ. 



Dorsal vertebrae, 1st, 4th, and a few joined together, numbers unknown. 

 Fragments of the sternum, and glenoid, and of scapula. 

 The fore limb bones nearly complete. 



Portions upper and lower end of femur ; the entire tibia, calcaneum, astra- 

 galus, and scapho-cuboid bones. 

 The remainder of the skeleton, chiefly ribs, vertebr?e, and pelvis, are constructed 

 on a comparative study of similar parts in kindred ruminants. 



EXPLANATION OF PLATE XIII. 



Design to illustrate the probable appearance of the living form of the Sivatherium, 

 male, female, and young. It shows the Frongbuck-hke horns, Saiga-]ike snout, and 

 other features appertaining to diverse kinds of existing Serbivores, which were com- 

 bined in this extinct form. 



III. — On the Eblativb Ages of Igneous Eocks. 

 By S. Allport, F.G.S. 



IN -the last number of the Geological Magazine there is an abstract 

 from an interesting and important paper by Prof. Hull and Mr. 

 Traill on the relative ages of certain igneous rocks of Co. Down, 

 Ireland. In that paper there is one paragraph on which I should 

 like to offer a few remarks, as it refers to a previous communication 

 from myself, and relates to a subject in which I take a special 

 interest. The paragraph is as follows : — " It might have been sup- 

 posed that microscopical examination would show some distinction 

 in the basalts of these geological ages, but recent investigations by 

 Zirkel, D. Forbes, Allport, and others, tend to show that there is no 



* 

 1 I refer the reader to Dr. Malcolmson's Geological Deductions, etb., Geol. Trans. 

 ser. 2, vol. v., p. 570 ; Journ. Bombay Geograph. Soc. 1841-44, p. 371 ; and Falconer's 

 criticism thereon in his " Fossils of Perim Island." 



