Vol. 59.] 



GEOLOGY OP PATAGONIA. 



161 



Aires, published a classification based on his observations in Southern 

 Patagonia. Both are summarized here in tabular form : — 



Classification of Patagonian Sediments, 

 after m. alcide mercerat. 



System. 



Ser 



Pleistocene. Terrestrial Deposits 



Upper Tehuelche. Pebble- 

 Bed. Basalt-mesetas. 

 i Middle Tehuelche. Lig- 

 Tehuelche. ■ nitiferous sands, with 

 O street Remondi. 

 Lower Tehuelche (Ostrea 

 Torresi). 



Period. 



Pleistocene. 



Plioc< 



Mi 



Mr. Hatcher's Classification. 



Shingle Formation. Pleistocene. 

 Cape Fairweather Beds. j Pliocene. « 



Santa Cruz Beds. 



Patagonian Beds. 



Miocene. 



Upper Lignites. 



Magellanian Beds. 



(Unconformity.) 



Oligocene. 



Eocene. 



Guaranitic Beds. 



Santa Cruz. 



Upper Santa Cruz (Ostrea 



Ferrarisi). 

 Lower Santa Cruz (Ostrea 



Bourgeoisi). 



j Upper Patagonian (Ostrea 



Patagonian. L P<*tagonica). 



ta&u Lower Patagonian and 



Fi/rotherium-Beds. 



Conglomerates and lig- 

 nitiferous sands. 

 Guaranitic. Red sands with Dinosauria. 



Limestones, with Inoce- 

 ramus (?) 



Eocene. 



Laramie. 



Lower Lignites 



Variegated Sandstones. 



Upper Conglomerates. 



Cretaceous. 



Cretaceous. 



Belgrano Beds. 



Conglomerates. 



Gio Beds. 



Mayer Shales, with im- 

 perfect remains of 

 Ammonites. 



Jurassic. 



During several months' travelling in Patagonia 1 had opportunities 

 of gaining some knowledge of the geology of the country ; but, 

 owing to the great distance traversed in the time, I found that it 

 was impossible to study the stratigraphy satisfactorily, except in the 

 neighbourhood of Santa Cruz, where a few weeks were spent. In 

 that district the Patagonian and the Santa Cruz Beds are excellently 

 exposed, as also is the ' gravel-formation,' which, in order to avoid 

 any confusion, will be referred to hereafter as the Tehuelche Pebble- 

 Bed. 



Pig. 1 (p. 162) represents a section of the Patagonian Beds 1 

 at Entrance Point, at the mouth of the Kio Santa Cruz. The divisions 

 mentioned by Darwin in ' Geological Observations ' lie respectively 

 between the 272-foot and 220-foot levels, the 220-foot and 159-foot 

 levels, the 159-foot level and the talus-marks. These beds were 

 also examined 18 miles up stream, on the estancia of Don Pedro 

 Ptichmond, where they yield a rich invertebrate fauna. The section 

 here does not present so varied a lithological character as that at 



For the fauna of the Patagonian Beds, see Dr. Ortmann's Eeport above 

 quoted. 



