M, K. Biot on Earthquakes. 143 



in many places the earth was cleft, and from these openings 

 sand issued, and stones and water, which covered all the flat 

 country. In 1305, the earth opened up in two places, and 

 thence issued water, which was quite black. In 1567, the 

 earth opened in many places, and from these fissures there 

 flowed torrents of water and black sand. In the year 125, the 

 hill You Tone tumbled down and killed more than 400 persons. 

 In 634, a mountain fell from top to bottom, and was broken 

 into mere fragments. In 887, another mountain fell, and the 

 sun's light was obscured by the dust. In 999, near the Yel- 

 low River, and during a time of much rain, the side of a moun- 

 tain slipped down, and destroyed twenty-two families. 



In regard to these latter observations, M. Boussingault 

 makes the following remarks : " The downfall of mountains 

 is often noticed in the Catalogue of M. Ed. Biot. These 

 falls have not always been preceded or accompanied with oscil- 

 lations of the soil. The same phenomena, and equally inde- 

 pendent of earthquakes, frequently occurs in the Andes, espe- 

 cially in those regions which consist of porphyritic and trachy- 

 tic rocks. Geologists have probably not sufficiently directed 

 their attention to the fragility of the mountains of the zone in 

 question. A number of examples might be quoted which de- 

 monstrate the identity of the phenomena. Thus, in the year 

 1818, at seven in the morning, a portion of the peak of Tacon, 

 at the north-eastern extremity of the Vega de Zupia, slipped 

 down, and carried along with it a hundred Indians who culti- 

 vated the sugar-cane at the foot of that porphyritic mountain. 

 This crash produced a thick dust, which by many was mis- 

 taken for smoke. Even at the present day the debris of the 

 rock forms a kind of slope which occupies an extent of many 

 furlongs."*' M. Boussingault cites many examples of this kind, 

 and then continues : " The geological catastrophes collected 

 together in M . Biot's memoir appear, therefore, similar in their 

 effects to the analogous phenomena which have occurred, and 

 which still continue to occur, in South America ; and since, in 

 spite of the labours of the modern schools, there are still those 

 who hesitate, and even refuse, to admit the occurrence of ele- 

 vations and depressions of the earth's surface, and who, in a 

 word, maintain the stability of the crust of the earth, it was 



