THE PERUVIAN COASïLANDS. 



285 



is brought to the surface by filtration through the upper strata, and sometimes 

 even gases and fatty substances ooze up. 



South of Sechura some hills of similar formation are perhaps even richer still 

 in underground reservoirs of petroleum, while the surface on the coast plains 



Fig. 110. — Amotape Mountains. 

 Scale 1 : 1,200,000. 



Dep'hs. 



Oto 10 

 Fathoms. 



10 to 50 

 Fathoms. 



ftO to 500 

 Fathoms. 



18 Miles. 



500 Fathoms 

 and upwards. 



bubbles up, so to say, in miniature volcanoes, 30 feet high and 650 in circum- 

 ference, from which the bitumen escapes in a liquid state, often mixed with salt 

 water, and rapidly solidifies on the ground. The Garita and Reventazon plains 

 near the sea are dotted over with hundreds of these hillocks of hardened pitch. 



