ORGAN MOUNTAINS. 493 



account of this singular formation, the glacial phenomena 

 which abound in the Organ Mountains are of a peculiar 

 character. At first, I was at a loss to explain how loose 

 masses of rock, descending from the heights above, should 

 be caught on the edges of these basins, instead of rolling 

 to the bottom. But their position becomes quite natural 

 when we remember that the ice must have remained in 

 these depressions long after it had disappeared, or nearly 

 disappeared, from the slopes above. Hindered from ad- 

 vancing, these huge masses of rock have become gradually 

 embedded in the soil, and are now solidly fixed in positions 

 which would be perfectly inexplicable, unless we suppose 

 the basin to have been formerly filled with something which 

 offered an obstacle to their farther descent. Moraines also 

 abut upon these depressions, coming to an abrupt close 

 upon their margin. Morainic soil that is, masses of drift 

 with all sorts of loose materials buried in it abounds 

 everywhere in this region ; but, on the whole, the glacial 

 phenomena are difficult to study, because the heavy growth 

 of forest has covered all inequalities of the soil, and, except 

 where sections have been made or ground has been cleared, 

 the outlines are lost." 



This was our final excursion in Brazil. The next morn 

 ing we returned to the city ; and the few remaining days 

 were spent in preparations for departure, and in bidding 

 farewell to the friends who had made Rio de Janeiro almost 

 like a home to us. Among the pleasant incidents of this 

 last week, was a breakfast given by Mr. Ledgerwood, who 

 was then conducting the business of the American legation 

 in the temporary absence of our Minister, General "Webb. 

 This occasion, at which Mr. Agassiz was invited to meet 

 several members of the Brazilian administration, gave him 



