84 Mr Toplis on Hydrostatical Pressure 



on Fossil Fishes, and which I supposed might be referred to 

 my genus Hypsodon, is a scale of Cladocyclus. The teeth of 

 the Brazilian Cladocyclus, which I have observed on a speci- 

 men furnished with scales, leave no doubt as to their generic 

 difference. 



2. Calamopleurus. Scales circular ; tube of the lateral line 

 straight and very short ; trunk cylindrical, which induces me 

 to term the species Cal. cylindricus. 



I shall publish detailed figures and descriptions of these 

 fishes, as complete as the materials I have examined admit 

 of, in one of the supplementary parts of my work on Fossil 

 Fishes. 



On Hydrostatical Pressure as a Cause of Earthquakes. By 

 the Rev. John Toplis, B. D., South Walsham, Norfolk. 

 Communicated by the Author.* 



Amongst the various causes brought forward to account for 

 the phenomena of earthquakes, the writer of this article is not 

 aware that they have ever been attributed to that of hydro- 

 statical pressure. Perhaps this action may account in some 

 instances for the circumstances which attend the convulsions 

 of the eai'th's surface. Those which are most violent gene- 

 rally occur near the sea in the neighbourhood of the highest 

 mountains, which would afford the greatest pressure, upon the 

 supposition of their containing columns of water communi- 

 cating with that under the surface where the eruption takes 

 place, of sufficient altitude to produce such an effect. The ver- 

 tical columns may be supplied by the water condensed from 

 the aqueous vapour passing over their cold or snow-covered 

 summits. 



In order to remove any doubts with respect to the power 

 arising from hydrostatical pressure being able to produce earth- 

 quakes, it may be observed, that the weight of a cubic foot of 

 water is about 1000 ounces avoirdupois ; consequently, that 

 of a column of water of an equal base, 500 feet in height, 



* Read before the VVerncrian Society. November 14. 1040. 



