THE AGE OF THE WORDD.

Globe, Volume XXII, Issue 1836, 10 January 1880, Page 2

THE AGE OF THE WORDD.

“ A New Estimate of the Age of the World" is the title of a paper recently read before the Bojal Society, London, by G. Mellard Bead, of Liverpool. Upon the paper the “ Academy ” remarks : “ Geologists, astronomers, and physicians alike have hitherto been baCLd in their attempt to set up any satisfactory kind of a chronometer which will approximately measure geological time, and thus give us some clue to the antiquity of our globe. It is, therefore, worth noting that Mr Mellard Bead, of Liverpool, has lately contributed to the Eoyal Society a very suggestive paper, in which he enleavers to grapple with the question by employing the limestone rocks of the earth’s crust as an index of geological time. Limestones have been in coorse of formation from the earliest known geological periods, but it would appear that the Lite found si rata are more calcareous than the earlier, and that there has, in fact, been a gradual progressive increase of calcareous matter. The very extensive deposition • f carbonate of lime over wide areas of the ocean bottom at the present day is sufficiently attested by the r< cent soundings of the Challerger. According to the author’s estimate, the sedimentary crust of the earth is at least one mile in average actual thickness, of which probably one-tenth consists of calcareous matter. In seeking the origin of this calcareous matter, it is assumed that the primitive rocks of the original crust was of the nature of granite or basaltic rocks. By the disintegration of such rocks, calcareous and other sedimentary deposits have been formed. The amount of lime salts in water which drain districts made of granites and basalts is found, by a comparison of analyses, to be on an average about 3 - 73 parts in 100,000 parts of water. It is further assumed that the exposed area of igneous rocks, taking an average throughout all geological time, will bear to the exposures of sedimentary rocks a ratio of about one to nine. From these and other data Mr Bead concludes that the elimination of the calcareous matter now found in all the sedimentary strata must have occupied at least 6CO millions of years This, therefore, represents the minimum ago of the world. The author infers that t ha formation of the Laurentisn, Cambrian, and Silurian strf.ti must have occupied about two hundred millions of years ; the old red sandstone, the carboniferous, and the Poikilitie systems another two hundred millions ; and all the other strata, the remaining two hundred millions. Mr Bead is, therefore, led to believe that geological time has been enormously in excess of the limits urged by Certain physicists ; and that it has been ample to allow for all the changes which, on the hypothesis of evolution, have occurred in the organic world.”