474 Reviews — Eartltquake of Marsica. 



north of the Azores. This, he says, must have solidified on the 

 surface of the land, as it would have solidified at least into a crypto- 

 crystalline condition at the depth of 3,0.00 m. where it was found^- 

 This fact, coupled with the great inequality and rocky character 

 of the ocean floor at this spot, where the ooze only lies in the 

 hollows, shows that the submergence must not only have been recent 

 but also sudden, as there had been no time for the inequalities of the 

 surface to be eroded. 



Turning to the zoological evidence, the author quotes work by 

 M. Louis Germain to show, firstly, that the terrestrial fauna of the 

 Azores, Madeira, the Canaries, and Cape Verde Islands is of conti- 

 nental origin, and shows evidences of adaptation to desert conditions. 

 Secondly, that the Quaternary formations of the Canaries and 

 Mauretania contain the same species of Helix. Thirdly, that the 

 mollusca of the four archipelagoes have affinities with the Tertiary 

 mollusca of Europe ; and, fourthly, that the Oleacinidte group of 

 pulmonate mollusca is confined to the Mediterranean basin, the 

 Azores, Canaries, Madeira, the West Indies, and Central America. 

 All this evidence seems to demand the existence of a continent 

 connecting Europe and Central America which gradually disappeared, 

 beginning with the westerly portions and leaving the easterly portions 

 till the last, and the author considers that it is quite conceivable, if 

 we take into account the unstable condition of the Atlantic volcanic 

 areas, that the final disappearance may have been witnessed by man, 

 and have been so sudden as to constitute a " cataclysm ". 



"W. H. WlLCOCKSON. 



V. — The Earthquake in the Marsica, Central Italy. By 

 Professor Ernesto Mancini. Smithsonian Report for 1915, 

 pp. 215-18. 



ON January 13, 1915, the Marsica, a district in the southern part 

 of the Aquilian Abruzzi, was devastated by a very severe 

 earthquake. The region of the Marsica which was the epicentre of 

 the disturbance is situated on the line along which, according to the 

 Japanese seismologist Professor Omori, the chief earthquakes in Italy 

 have been distributed. The district is essentially sedimentary and 

 of Karstic origin, so that a volcanic origin is impossible, and the 

 shock seems to have been caused by two separate deep-seated move- 

 ments which took place either simultaneously or in very quick 

 succession along a line having a north and south trend, some sixty or 

 seventy miles east of Rome. The shock was of such intensity that 

 the seismograph at Rocca di Papa was dismounted, as also would 

 have been the instrument at Rome had it not been provided with 

 special stop screws. The details of the seismic waves have been 

 worked out by Professor Oddone. Their period was 0*7 second, 

 their wave-length 20 metres, and their amplitude 20 centimetres. 

 The damage to buildings was caused by a bulging movement of the 

 ground, accentuated by eddying motions due to the combination of 

 longitudinal and transverse vibrations coming from the hypocentre 

 to the epicentre at the surface. 



