166 



THE GEOLOGIST. 



runs— the "Frenchman's Lead," "White Horse Lead," and "Terrible Lead," 

 running parallel to each other in a direction transverse to that of the present 

 gully, and from hill to hill. Like all other "leads," these rise generally in the 

 neighbourhood of a quartz- vein (or "quartz-reef"), are shallow at first, 2 or 3 

 feet in depth, and gradually get deeper. 



4. " On the Gold-diggings at Ballaarat." By H. Rosales, Esq. In a letter to 

 W. W. Smyth, Esq., Sec. G. S. 



" By the aid of machinery, and through the alteration of the mining regula- 

 tions granting extended claims, the old ground has been profitably re-worked ; 

 and, by the introduction of the frontage-system, which, according to the difficul- 

 ties to be overcome, grants extensive claims on new ground, the present ' leads,' 

 most of which are N. W. of the Gravel Pits, under the townships, are advantage- 

 ously worked. The amalgamation of three or more claims is also allowed, the 

 miners having then to put down only one shaft. 



" The engines most in use are stationary, of from 15 to 20-horse power, with 

 winding and reversing gear. To the end of the winding-gear shaft is attached 

 the crank for the pump, and the motion is also taken to drive a puddling machine, 

 which is nothing but the arrastra working without mercury. The depth of 

 sinking averages about 300 feet, of which in some instances there are as much as 

 200 of basalt to be cut through. 



" At the junctions of the Frenchman's and White Horse Leads, in the Eldorado, 

 the remains of a tree were found in an undisturbed position, with the roots fast 

 in the wash-dirt ; and it might be interesting to you to know that at Poverty 

 Point the deep channel, with a N.W. strike, is crossed at about 140 feet higher by 

 the shallow channel, which has a strike of N.E. by E., and which again in its turn 

 is crossed, at a level of 20 or 30 feet still higher, by the present water-course, the 

 strike of which is W." 



5. " Notes on some Outline- drawings and Photographs of the Skull of Zygoma- 

 turus trilohus of Macleay, from Australia." By Prof. Owen, F.R.S., F.G.S. 



About a month since Prof. Owen received from Sir R. Murchison seven photo- 

 graphs, three of which are stereoscopic, of perhaps the most extraordinary mam- 

 malian fossil yet discovered in Australia. 



These photographs, with a brief printed notice of their subject by William 

 Sharp Macleay, Esq., F.L.S., and some MS. notes by J. D. Macdonald, M.D., R.N., 

 had been transmitted to Sir R. Murchison by His Excellency Governor Sir W. 

 Denison, from Sydney, New South Wales ; and by request of Sir Roderick the 

 Professor brought the subject under the notice of the Geological Society of London, to 

 whom Sir Roderick desired to present the photographs on the part of His Excellency 

 Sir W. Denison. 



Professor Owen had some weeks previously received from George Bennett, Esq., 

 F.L.S., of Sydney, outlines of the same fossil skull, made by him on the reception 

 of the specimen by the authorities of the Australian Museum at that town ; and 

 the Professor had penned notes of his comparisons of these sketches before 

 receiving the photographs and descriptions of the fossil skull from Sir R. L Mur- 

 chison. 



This unique and extraordinary skull of a probably extinct mammal, together 

 with other bones, but without its lower jaw, were found at King's Creek, Darling 

 Downs — the same locality whence the entire skull and other remains of the 

 Diprotodoii have been obtained. 



Mr. Macleay has desbribed the fossil under notice as belonging to a marsupial 

 animal, probably as large at an ox, bearing a near approach to, but diflFering 

 gcnorically from, Diprotodon. He has named it Zygomatunis trilohus. The skull 

 has transversely ridged molars, and a long process descending from the zygomatic 

 arch, as in the Mcgidhnium ;ind Diprotodon, and exhibits an extraordinary width 

 of the 7ygomatic arches. The skull at its broadest part, across the zygomata, is 

 1 5 inches wide, and is 18 inches long. In Diprotodon the skull is about 3 feet long 

 by 1 foot 8 inches broad : so that while the latter must have had a face somewhat 

 like that of the Kangaroo, the Zggoiiiaturus more resembled the Wombat in the 

 face and head. 



