F. GEOGRAPHY. 207 



ry fossils is recorded. The cliffs were largely composed of 

 them. The original programme had included a reconnois- 

 sance of the rivers Negro and Santa Cruz, and a visit to the 

 Falkland Islands, where Professor Agassiz especially desired 

 to inspect the so-called " rivers of stone," believing that they 

 are of glacial origin ; but the circumstances of the vessel 

 and the lateness of the season made it important to proceed 

 with haste, and this part of the scheme was reluctantly relin- 

 quished. No other point was visited between the Gulf of 

 San Mathias and the Straits of Magellan, though a cast of the 

 dredge was made off the Gulf of St. George, which was re- 

 warded with some superb star-fishes of immense size (astro- 

 phyton, or basket-fish), besides other valuable specimens. 



The vessel rounded Cape Virgins on the 13th of March, and 

 made its next anchorage at Possession Bay. Accounts of 

 the work in this region have already been published in Pro- 

 fessor Agassiz's reports. The most important results obtained 

 in this locality were Count Pourtales's discovery that Mount 

 Aymon is an extinct volcano, with a very perfect centre, and 

 forming the nucleus, as it were, of a cluster of smaller vol- 

 canoes, and some geological observations less striking by 

 Professor Agassiz, which, however, it is not important to de- 

 tail at present. 



Three weeks were passed in the Straits of Magellan and in 

 Smythe's Channel, the vessel anchoring at the close of each 

 day. The zoological results throughout this region were very 

 satisfactory. Large collections chiefly marine, of course 

 were made ; but the glacial phenomena were here even more 

 deeply interesting than the fauna. From the character of 

 the drift, and the constant presence of erratic materials, evi- 

 dently quite foreign to the soil, and recurring along the Pat- 

 agonian coast throughout the Straits of Magellan, and, as 

 was afterward found, high up on the Chilian coast; from the 

 glacier-worn surfaces on the two sides of the Straits as com- 

 pared with each other, and on the walls of Smythe's Channel, 

 it was evident that there has been a movement of ice from 

 the south northward, preceding all local glacial phenomena, 

 the latter being, indeed, only the remnant of the former. 



Leaving Smythe's Channel, the Hassle?' kept along the coast 

 to the southern end of Chiloe Island, making a run up the 

 Gulf of Carcorado, in the hope of passing through the Archi- 



