Show n Where Tree Trunks Turn Tu o to Rainbows in Humboldt County Nevada in the heart of IN the great natural wonderland of the West Vest writes write H. H P. P Whitlock Curator of the Department Department Depart Depart- ment of or Mineralogy i of the American Museum of Natural History there have quite recently been brought to light some ome wonderful fossil remains of trees These are remarkable not merely because be- be because be cause they arc are trees which have been turned to stone but because the stone is the much sought 1 after opal which has of late years taken a high place among amon the popular gems cems To ITo reconstruct the process by which this miracle of nature has ins come about we must goback go goback back many thousands of years to the time when time when these trees clothed the mountain sides or shaded the valleys over which roamed the mastodon and the tooth sabre-tooth tiger tiger tiger-a a landscape far different from rom that we see today from the train trail window orthe or orthe orthe the pack-horse pack trail We Ve must conceive this country overwhelmed by some widespread disaster disaster disaster dis dis- dis- dis aster possibly one ono of oi the earthquakes which mu must t have been frequent in such a n volcanic region region re re- re gion which reduced the growing gro forest to a swamp and buried the tree trunks under many feet of or water soaked debris It was then when the trees had become mere water-logged water snags that the process which converted them then into opal began For the water which penetrated to their inmost impost pores was not the innocent fluid we wo are accustomed to dip from a wayside pond but a amore amore amore more or less heavily charged solution of silica probably heated by volcanic action 1 n M 1 11 NN N M Such a mineral water gradually as aa the woody substance of the tree yielded to decay replaced replaced re re- placed this substance particle for particle with hydrated silica often preserving with wonderful fidelity the cellular structure of the wood Much of the opal into which the wood has been transformed transformed trans trans- formed is of the variety called semi-opal semi but some of the colloidal silica has been deposited as precious opal and exhibits all aU the beautiful and changing color of that gemA gemA gem A A fine firle and hi highly representative series of oi these Nevada wood-opal wood replacements has been put on view in the Morgan Hall of Minerals in inthe inthe inthe the American Museum of Natural History New NewYork NewYork NewYork York city Here all the steps in the process of transformation of wood into opal may be seen NN N w. w 1 NN |