spybot nln thine 




1891.] Geology and Paleontology. 817 
The vast depth of water to the south of the island, and the long 
unbroken sweep of the ocean in the same direction, prepare one to 
believe anything might be possible when that vast body of water was 
urged on bya tropical hurricane. The illustration shows the hurricane 
beach above and the present line of the water below. (Plate xvi.) 
The most obvious lesson of this special case is a due caution in 
reasoning on shore elevations, unless all the elements of the problem 
`- are absolutely known.—J. T. ROTHROCK. 
New Acquisitions to the Eocene Fauna from Southern 
Patagonia.—In a letter dated May 5th, 1891, M. Florentino Ameghino 
informs us of the paleontological researches of his brother, Carlos 
Ameghino, on the borders of the river Gallegos, in Patagonia,— 
whose former researches we have already made known to our readers. 
The new results may be summed up as follows : 
1. The lemurs (Prosimiz) are for the first time found in the Eocene 
of Patagonia. 
2. The discovery of new species of Microbiotheriide in good con- 
ditionsserves to confirm the opinion advanced by M. Ameghino in his 
last work on the Plagiaulacide. The Microbiotheriidz have multiple 
incisors (four on each side), and so seem to represent the ancestral 
type of the Plagiaulacidse and of the Diprotodont Marsupials. 
The same formation furnished an entirely new group of Plagiaula- 
cidze with multitubercular molar teeth, but with the same dental for- 
mula as the species already known. ‘The last molar is, however, 
entirely rudimentary. These new types connect the Plagiaulacide of 
Patagonia previously described with the Plagiaulacidz of Europe and 
of North America. (Revue Scientifique, July 4th, 1891.) 
The Progress in Geology for the Years 1887-1888.—In a 
résumé of the geological work done in the years 1887-1888, Mr. 
W. = McGee cites the following as the most important: 
. The transition from an empiric classification in geology to a nat- 
al one by processes or by fundamental principles and laws. 
2. The birth of the new geology, which interprets geologic history 
from the records of degradation, as e old geology did from the 
records of deposition. 
3. The invention of a method of determining the depth of earth- 
quake centers and of the velocity of earthquake transmiŝsion. 
4. The recognition and definition of a great geologic group,—the 
Algonkian, and also of a subgroup of rocks,—the Lower Cretaceous, 
and the correct determination of the succession of the subordinate 

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