278 Reviews — F. Priem — Fish from Chalk of France. 



of the earthquake and on the distance of the place of observation 

 from the epicentre. 



In the case of slight local earthquakes, the first movements are 

 rapid vibrations superposed on small oscillations of longer period. 

 When the vibrations cease, the oscillations become more marked, and, 

 as a rule, the mean position of the pendulum undergoes a continuous 

 change, showing that the ground receives a tilt which, after reaching 

 a maximum value, disappears more or less slowly. On May 25th, 

 1895, for example, a slight earthquake occurred at Rovigo, which 

 lies about twenty miles south of Padua. Joining the mean points of 

 all the oscillations recorded by the two pens, the components are 

 obtained of the path along which the pendulum would have moved 

 if it had followed the tilts of the ground slowly and without 

 oscillating. The resultant path is found to be nearly a straight line 

 running N. 32° W. and S. 32° E. During the first ten seconds the 

 tilt of the ground took place slowly ; in the next twelve seconds it 

 rapidly increased to a maximum of about 6"; and then, during 

 the next ten seconds, it returned as rapidly towards its original 

 position, which, however, it only reached after other small 

 oscillations of about twenty seconds' duration. 



The more distant the epicentre, the longer is the first phase of the 

 movement, namely, that which consists of rapid vibrations super- 

 posed on small oscillations. As a rule, both of these take place 

 about a line indicating a very slight tilt of the ground. If the 

 shock be strong and the epicentre distant, this first phase may last 

 for about a minute. The second phase consists of large oscillations 

 with various maxima, which begin and end suddenly. The third 

 and last phase is characterized by small irregular oscillations, much 

 slower than the preceding. Throughout both of these phases, the 

 mean position of the pendulum continually changes, as if long, slow 

 waves, with a period of at least twenty seconds, were at the same 

 time propagated across the ground. 



In the diagrams corresponding to disastrous shocks with a very 

 distant epicentre (such as, for example, the Japanese and Argentine 

 earthquakes of 1894), the different phases of the movement are 

 separated from one another. The first consists of vibrations, of 

 abrupt displacements, and small oscillations ; in the second phase, 

 the lines are irregular and deeply sinuous, though interrupted by 

 sudden displacements of small amplitude; while, in the third, the 

 lines become regular and sinuous, indicating a slow and gentle 

 rocking of the ground with a period of about thirty seconds. 



C. Davison. 



IV. — Fish-remains from Phosphatic Chalk in France. (Sur les 

 Poissons de la Craie Phosphatee des Environs de Peronne.) 

 By F. Priem. Bull. Soc. Geol. France [3], vol. xxiv, pp. 9-23, 

 pis. i, ii (1896). 



THE stratigraphical distribution of fossil fishes in the Chalk is 

 a subject deserving more careful attention than it has hitherto 

 received. Detailed descriptions of remains from definite horizons 



