160 Account of (he Proceedings of the 



mass becomes colder, and the steam arriving from where it is formed, 

 not being able to force the water out, is condensed by that filling the 

 channel, the increased heat of which is transmitted to the bottom of 

 the pipe. The water in the channel becomes boiling, and the 

 steam, no longer condensing, acquires great power by compression, 

 and finally drives out the water through the pipe. The same facts 

 having been observed at the Strokkur, the same explanation is of- 

 fered. 



M. Dumont, in a memoir on the value of the palseontological cha- 

 racter in geology, endeavours to ascertain the aid geology may de- 

 rive from organic remains : first, as regards the relative age of su- 

 perimposed beds in the same country ; secondly, in comparing the 

 dates of I'ocks situated in counti'ies remote from each other ; and, 

 thirdly, in order to fix the limits of formations. He concludes, after 

 entering upon detail, that fossils are valuable in the same country in 

 determining the relative age of x'ocks formed at epochs very distant 

 from each other, while they gradually lose this value as the forma- 

 tion of the beds approached each other in geological time. Under 

 the second head he infers that analogous beings have existed in dif- 

 ferent localities at different times, that the series of organisms be- 

 longing to different latitudes have commenced at distinct epochs by 

 analogous species, and that the organized beings existing at the same 

 time ill the various geographical zones were as different formerly as 

 they are now. With respect to the limits of formations, M. Dumont 

 concludes tliat palasontological divisions cannot exactly accord with 

 the geological divisions founded on the revolutions of the globe. 



In some reflections on the nature and application of characters 

 for determining rocks, M. FrapoUi remarks that, zoological charac- 

 ters being only of comparative value, and mineralogical considera- 

 tions constantly leading us wrong, it is to superposition of rocks, or 

 their stratigraphical arrangement, that we must look for the sole 

 true base of geological science, and that our principal attention should 

 be directed to it when determining unknown formations. M. Fra- 

 poUi passes in review the hypothesis of the original igneous fluidity 

 of the earth and its consequences, as the heat radiated into space 

 and the crust became solid, adverting to times of repose and frac- 

 ture, the accumulation of sedimentary deposits and their upheaval, 

 and especially referring to secular upheavals and their results. 



M. de Verneuil read a note on the parallelism of the pala30zoic 

 rocks of North America and Europe, followed by a table of the fos- 

 sil species common to the two continents, with the indications of the 

 groups in which they are found, and a critical examination of each 

 of the species. In this communication M. de Verneuil, describing 

 the composition of the pala30zoic rocks of New York, of which he 

 enumerates the twenty-eight groups into which they have been di- 

 vided by the New York State geologists, points to the excellent suc- 

 cession of beds observable in that part of North America. He also 



