EASTERN STATES SOUTH OF THE AMAZONS. 137 



plains, even some bold peaks, the whole terminating westwards in an abrupt cliff 

 1,000 feet high, surmounted by a phonolitbic column in the form of a colossal 

 lighthouse. 



The governor of the island refused the naturalists of the Challenger permission 

 to explore it ; but since then it has been studied by the geologist Branner and the 

 zoologist Ridley, and it is now well known. The basalts of which it largely con- 

 sists are of ancient date, and since the discovery no eruption has taken place. 

 The lava flows occurred at a time when the island was submerged to a depth of 

 about 75 fathoms, as shown by the cakes of coral attached to the basalt columns 

 at this height above the sea. 



The other islets lying in mid-Atlantic on the same axis as Fernando de 

 Noronha are jagged serpentine rocks, flecked with patches of white guano and 

 almost inaccessible. Penedo de S. Pedro, highest of these reefs, lying near the 

 track of the steamers plying between Pernambuco and Saint Vincent, presents the 

 aspect of a row of pillars rising abruptly above the surface. In these waters sea- 

 quakes are a frequent phenomenon. 



Cltmate. 



In these tropical lands the mean temperature varies little throughout the year, 

 at Pernambuco not more than 3° Fahr. between the wet and dry seasons. Even 

 the average lowest (July) and the average highest (February) show a range of 

 only about 5° or 6° Fahr, 



On the north-east coast the normal wind is the south-east trade, usually called 

 the " general wind.^' Coming from the circumpolar Antarctic regions, it tempers 

 the heats, at least on the seaboard, and also coincides with the wet season from 

 December to June, when the rainfall in ordinary years sufiices to nourish an 

 exuberant vegetation. Some districts, such as Maranhiio, are exposed to frequent 

 thunderstorms, followed by heavy downpours. But at Pernambuco, although the 

 rains are very heavy, whole years sometimes pass without any electric discharges. 

 Even the rains themselves are often delayed, or cease to fall before the end of the 

 normal wet season. The droughts which ensue, especially in the interior, are 

 accompanied by great changes of temperature, which is very high during the day 

 in an atmosphere charged with dust, and relatively low during the clear nights 

 owing to the excessive radiation. In this respect there is a great contrast between 

 the climate of the coastlands, where two out of three days are rainy, and that of 

 the inland districts, where the proportion is reversed.* 



Floka and Fauna. 



The vegetation, corresponding with the climatic differences, is extremely rich, 

 and presents the same species as Amazonia on the well- watered coastlands, and 



* Meteorological contrast between the coast and the sertao (interior) : — ■ 



Temperature. 



