204 Dr. G. KrefFt o;i Professor Oweii's 



calcareous rocks belonging to the Cambrian system may 

 yet be found ; but considerable doubts may be entertained 

 of their occurring in it to any extent except as metliylosed 

 members. 



The facts brought to light by the various submarine surveys 

 that have been made show how simple, yet grand, are the 

 depositional phenomena of the ocean ; but tliey place before the 

 geologist notiiing more than the materials that enter into the 

 com])osition of ordinary sedimentary rocks in their normal 

 condition. During the ^\'erncrian stage in the ])rogress of 

 geology the doctrine was taught that crystalline rocks were 

 the products of oceanic precipitations. Other doctrines took 

 its place. Of late years, however, it has been revived, with 

 novel accessories. Judging from the results of the surveys 

 referred to, the chances seem to be extremely remote that any 

 sea-bottoms will ever yield to the dredge samples of direct 

 crystalline precipitates having the least relation to the Lauren- 

 tian diorites, ophites, syenites and the like, as products of 

 our present oceans. 



XXVII. — Bemarks on Professor Owen''s Arrangement of the 

 Fossil Kangaroos'^ . By Gerard KREFFTf. 



The first part of Professor Owen's work describing the fossil 

 kangaroos has just been received ; and as some new genera 

 have been added, it will no doubt interest readers of the 

 * Sydney Mail ' to hear how these divisions have been defined. 

 The learned Professor pays a just tribute to John Gould, 

 F.R.S., " through whose adventurous journeys, and by the 

 noble works in which he has given the result of his observa- 

 tions in Australia and Tasmania, we mainly know the extent 

 and kinds of variations under wliich the kangaroo there exists." 

 There is more in this sentence than many people imagine, 

 because Professor Owen no longer hesitates to speak " evolu- 

 tionally " \ about the subject. It has been pointed out by me 

 on several occasions, and chiefly in papers read before the 

 Royal Society of New South Wales, that the Avhole of our 

 extinct and living marsupials were oftshoots or brandies of a 

 kind of animal which combined the dental structure of both 

 the carnivores and herbivores of the marsupial section. The 



* " On the Fossil Mammals of Australia. — Part VIII. Family Macro- 

 podidfe : Genera Macropns, PhoHcoIagus, Sthenunis, and Pi-otemnodon 

 (Phil. Trans. 1874, pt. i. pp. 24o-287, pis. xx.-xxvii.), by Professor 

 Owen, F.R.S. 



t From the 'Sydney Mail,' Dec. 26, 1874. Communicated by the 

 author. 



\ Royal Society's ' Philosophical Transactions ' for 1874, p. 2oo. 



