112 NORTHERN CHILE. 



the subterranean forces, should yield, crack, and 

 consequently tremble. It is, however, doubtful 

 how far this idea will explain the circumstance of 

 torrents of rain falling in the dry season during sev- 

 eral days after an earthquake unaccompanied by 

 an eruption ; such cases seem to bespeak sT)me 

 more intimate connection between the atmospheric 

 and subten-anean regions. 



Finding little of interest in this part of the ravine, 

 we retraced our steps to the house of Don Benito, 

 where I stayed two days collecting fossil shells and 

 wood. Great prostrate silicified trunks of trees, 

 embedded in a conglomerate, were extraordinainly 

 numei'ous. I measured one which was fifteen feet 

 in circumference : how surprising it is that every 

 atom of the woody matter in this great cylinder 

 should have been removed and replaced by silex 

 so perfectly that each vessel and pore is preserved ! 

 These trees flourished at about the period of our 

 lower chalk ; they all belonged to the fir tribe. It 

 was amusing to hear the inhabitants discussing the 

 nature of the fossil shells which I collected, almost 

 in the same terms as were used a century ago in 

 Europe, namely, whether or not they had been thus 

 " born by nature." My geological examination of 

 the country generally created a good deal of sur- 

 prise amongst the Chilenos : it was long before they 

 could be convinced that I was not hunting for mines. 

 This was sometimes troublesome. I found the most 

 ready way of explaining my employment was to 

 ask them how it was that they themselves were not 

 curious concerning earthquakes and volcanoes 1 

 why some springs were hot and others cold ] why 

 there were mountains in Chile, and not a hill in 

 La Plata? These bare questions at once satisfied 

 and silenced the greater number ; some, however 

 (like a few in England, who are a century behind- 



