124: EZEQUIEL 0RD0ÑEZ 



around it, and I figure its passage through the sediment- 

 ary rock like a screw acts through a piece of wood as what 

 concerns the ruechanical phenoinena. I imagine that dur- 

 ing the niaking of the pipes and coming of the masses of 

 hidden intrusive igneous material there was a certain ab- 

 sortion of the sedimentaries by the igneous molten material 

 in the depths, also the breaking of the sedimentaries near 

 the intrusión and finally a narrow aureole around the plug 

 of brecciated or broken material eaused by friction, which 

 zone is utilized in many cases for the rising of minute 

 quantities of oil to the surface and the formation of see- 

 pages of very slow accumulation. 



A number of large seepages near which important dis- 

 coveries have been made, are found at the foot of the necks 

 between the shale and the basaltic rock ; other seepages 

 lie in the flanks of dome shaped bosses. In no rare cases dry 

 hard cakes of "chapopote" with a soft freshly risen heavy 

 oil in the center, are encountered in the bottom of small 

 amphitheaters, or horse-shoe like encircling spaces, or in 

 general in the concavities made by curved rows of volcanic 

 hills and small ranges. These different cases of location of 

 seepages are very favorable for locating wells near them as 

 proved by experience (Cerro de la Pez, Chijol, Juan Ca- 

 siano, Cerro Azul, etc.). Numbers of small seepages or "cha- 

 popoteras" are found in the middle of the coastal plain far 

 from any salient topographical accident. It is frequently 

 observed then that the oil exude is not coming directly 

 from underneath the place as seen from the surface but 

 that it has run, some time for considerable distance on the 

 shale between it and the thick argillaceous material cover- 

 ing that rock. 



In the present state of our knowledge on the geology of 

 the oil lands it is difficult to explain some important pro- 

 ductive áreas near river banks without any apparent con- 

 nection with volcanic outbreaks neither with bosses. Unfor- 



