204 A JOURNEY IN BRAZIL. 



The character of the banks yesterday and to-day continues 

 unchanged ; they are rather high, rising now and then in 

 bluffs and presenting the same mixture of reddish drift and 

 mud deposit, with the gray, slaty rock below, cropping out 

 occasionally. This morning we are stopping to wood at a 

 station opposite the village of Fonte Boa. Here Mr. Agassiz 

 has had an opportunity of going on shore and examining this 

 formation. He finds a thick bed of ferruginous sandstone 

 underlying a number of thinner beds of mud clay, resem- 

 bling old clay slate with cleavage. These beds are overlaid 

 by a bank of ochre-colored sandy clay (designated as drift 

 above), with hardly any signs of stratification. Yesterday 

 we passed several lakes, shut out from the river by mud- 

 small number of species to be met with everywhere. It remains now to as- 

 certain with precision the limits of these ichthyological regions, and I may 

 perhaps be drawn on to devote some time to this study, if I find the means 

 of accomplishing it. There is a question which now becomes very iuterest- 

 ing ; it is to know how far the same phenomenon is reproduced in each one of 

 the great affluents of the river Amazons, or, in other words, whether the fishes 

 of the upper regions of the Rio Madeira, the Rio Negro, &c., &c., are the same 

 as those of the lower course of these rivers. As to the diversity of fishes in 

 the whole basin, my expectations are far surpassed. Before arriving at Mauaos 

 I had already collected more than three hundred species, that is to say, at least 

 three times the number of species thus far known. About half have been paint- 

 ed from life by Mr. Burkhardt ; if I can succeed in publishing all these docu- 

 ments, the information 1 shall be able to furnish on this subject will exceed all 

 that has been thus far made known. I should be very glad to learn that your 

 Majesty has not met with difficulties on the voyage, and has been able fully to 

 accomplish the ends proposed. We are here without news from the South 

 since we left Rio, and all we had learned then was, that after a very stormy 

 passage your Majesty had reached the Rio Grande. May God protect and 

 bless your Majesty ! 



With sentiments of the most profound respect and the liveliest grati- 

 tude, I am 



Your Majesty's very humble and obedient servant, 



L. AGASSIZ. 



