The Probability of Large Meteorites Having Fallen upon the Earth

E. H. L. Schwarz
1909 The Journal of geology  
From time to time the accumulation of new facts in any one science renders it necessary to examine into the cause for the existence of certain features, and to see whether some small points which rendered the earlier explanations not altogether satisfactory, may not be entirely accounted for in the light of the new experience. In many cases this proceeding has resulted in the entire recasting of our ideas concerning certain phenomena, especially in the physical sciences where laboratory
more » ... laboratory demonstration can prove the truth of the new law; in geology, the unwieldy nature of the subject-matter, and the different aspects which the same country or mountain may present to different observers, renders this method somewhat unsatisfactory. It must, however, be done, if the science is to progress, although in the end a categorical statement that the new explanation is a true one, and the old one a false one, cannot be made. It is the purpose of this paper to pick out certain facts in connection with the amygdaloidal lavas of Prieska, Cape Colony, which cannot readily be explained on any of the theories of igneous extrusion, and to see whether they cannot be accounted for on some other theory; I shall summarise what is known of the fall of large meteorites and point out in what way the phenomena connected with these show certain significant resemblances to those exhibited by the amygdaloids of Prieska, tentatively suggesting that in the past huge bolides fell on the earth, melted the rocks in the neighborhood of the fall and produced these great fields of lava. The meteorites that we examine in the collections of museums are small and would not by their fall make much impression on the earth: it is true that in the course of ages these small meteorites must add considerably to the bulk of the earth for it is estimated that some hundred thousands, if not some millions, of meteoric bodies fall upon the earth each day. Even these museum-specimen meteor- 124
doi:10.1086/621595 fatcat:kh3qf6fahreypnie5dbd67hfje