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VI. On a newly discovered Extinct Ungulate Mammal from Patagonia , Homalodonto- 
therium Cunninghami. By William Henry Flower, F.B.S. 
Eeceived May 30, — Bead June 19, 1873. 
The tertiary deposits of the east coast of Patagonia, which yielded to the researches of 
Mr. Darwin and Admiral Sulivan such interesting and aberrant mammals as Macrau- 
chenia , Eesodon, and Toxodon, have again disclosed a new and remarkable form of extinct 
animal life. The evidence upon which the existence of this new genus rests consists of 
a nearly complete set of teeth and some fragments of bone, discovered on the bank of 
the River Gallegos, by Dr. Robert O. Cunningham*, Naturalist to H.M.S. ‘Nassau.’ 
during the voyage undertaken for the purpose of surveying in the Strait of Magellan 
and the west coast of Patagonia in the years 1866, 1867, 1868, and 1869. The spot 
was visited in conformity with instructions received before leaving England, “ to insti- 
tute a search for a deposit of fossil bones discovered by Admiral Sulivan and the pre- 
sent Hydrographer of the Navy, Rear-Admiral G. H. Richards, about twenty years 
previously, and which Mr. Darwin, Professor Huxley, and other distinguished naturalists 
were anxious should be carefully examined” 
The conditions under which the specimens were found will be best understood from 
the following additional extract from Dr. Cunningham’s narrative. “ Accordingly, joined 
by the steamer, which again took us in tow, we proceeded onwards till we arrived 
opposite the first deposit of fallen blocks at the foot of the cliffs. The cutter was then 
anchored in the stream, while we pulled in towards the shore in the galley till she 
grounded, when we landed, armed with picks and geological hammers for our work. 
After examining the first accumulation of blocks, and finding in the soft yellow sandstone 
of which certain of them were composed some small fragments of bone, we proceeded 
to walk along the beach, carefully examining the surface of the cliffs and the piles 
of fragments which occurred here and there at their base. The height of the cliffs 
varied considerably, and the highest portions, averaging about 200 feet, extended for a 
distance of about ten miles, and were evidently undergoing a rapid process of disinte- 
gration, a perpetual shower of small pieces descending in many places, and numerous 
large masses being in process of detaching themselves from the parent bed. They were 
principally composed of strata of hard clay (sometimes almost homogeneous in its 
texture, and at others containing numerous rounded boulders) ; soft yellow sandstone ; 
sandstone abounding in hard concretions ; and, lastly, a kind of conglomerate, resembling 
* Now Professor of Natural History in Queen’s College, Belfast. 
t Notes on the Natural History of the Strait of Magellan and West Coast of Patagonia, 8vo, 1871, p. 279. 
