204 Dr. G. Krefft on Professor’ Owen’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 methylosed 
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 they place before the 
geologist nothing more than the materials that enter into the 
composition of ordinary sedimentary rocks in their normal 
condition. During the Wernerian stage in the progress 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 
erystalline precipitates having the least relation to the Lauren- 
tian diorites, ophites, syenites and the like, as products of 
our present oceans. 
XXVIT.—Remarks on Professor Owen's Arrangement of the 
Fossil Kangaroos*. By GERARD KREFFTT. 
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 which 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 whole of our 
extinct and living marsupials were offshoots or branches 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- 
podides: Genera Macropus, Phascolagus, Sthenurus, and Protemnodon 
(Phil. Trans. 1874, pt. i. pp. 245-287, pls. xx.-xxvii.), by Professor 
Owen, F.R.S. 
+ From the ‘Sydney Mail,’ Dec. 26, 1874. Communicated by the 
author. 
{ Royal Society’s ‘Philosophical Transactions’ for 1874, p. 255, 
