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 interest- 
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 Manaos 
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. 
