406 A JOURNEY IN BRAZIL. 



Coutinho, a member of the Brazilian government corps 

 of engineers, who, by the kindness of the Emperor, was 

 associated with me in my Amazonian expedition. I can 

 truly say that he has been my good genius throughout the 

 whole journey, saving me, by his previous knowledge of the 

 ground, from the futile and misdirected expenditure of 

 means and time often inevitable in a new country, where 

 one is imperfectly acquainted both with the people and 

 their language. We have worked together in this investi- 

 gation ; my only advantage over him being my greater 

 familiarity with like phenomena in Europe and North 

 America, and consequent readiness in the practical hand- 

 ling of the facts and in perceiving their connection. 

 Major Coutinho's assertion, that on the banks of the Ama- 

 zons I should find the same red, unstratified clay as in Rio 

 and along the southern coast, seemed to me at first almost 

 incredible, impressed as I was with the generally received 

 notions as to the ancient character of the Amazonian de- 

 posits, referred by Humboldt to the Devonian, and by 

 Martius to the Triassic period, and considered by all 

 travellers to be at least as old as the Tertiaries. The 

 result, however, confirmed his report, at least so far as the 

 component materials of the formation are concerned ; but, 

 as will be seen hereafter, the mode of their deposition, and 

 the time at which it took place, have not been the same at 

 the north and south ; and this difference of circumstances 

 has modified the aspect of a formation essentially the same 

 throughout. At first sight, it would indeed appear that 

 this formation, as it exists in the valley of the Amazons, is 

 identical with that of Rio ; but it differs from it in the 

 rarity of its boulders, and in showing occasional signs of 

 stratification. It is also everywhere underlaid by coarse, 



