Page:Popular Science Monthly Volume 76.djvu/591

Rh fossils, a stony framework of some kind is desirable, as we all know, but horny, or even the most perishable materials may be preserved under favorable conditions. Mr. Walcott's work on the Medusæ, and the researches of Ruedemann on the graptolites, as well as the work of others whom we can call to mind, are examples of excellent results from material of the latter nature, not to mention the hairs of the worm so carefully described by the Cincinnati paleontologist!

The metamorphism and apparently complete obliteration of all fossil remains in the rocks of certain large areas is likewise an apparently serious objection to the adequacy of the record, but here careful searching with the structural relations in mind will reveal the fossils, if present at all. The greatly folded and cleaved slates, schists and volcanic tuffs of the Piedmont area have long been the despair of both paleontologist and geologist, but at this meeting of the Geological Society of America, the State Geologist of Virginia will tell of Cincinnatian fossils in the so-called Algonkian and other schists and volcanics of the easternmost Piedmont of that state. In this case the discovery of well-preserved fossils was quite simple. It consisted merely in finding a place where the cleavage and stratification coincided, and then working hard.

Professor Calvin has spoken of the richness and beautiful preservation of certain Paleozoic faunas. While the beauty and occasional richness of such faunas is not to be gainsaid, we must not forget the many horizons and localities affording, in comparison, specimens so poorly preserved that they might readily furnish an argument for the inadequacy of the record. Nor must we forget that in quite a portion of the geologic column organic remains are not only poorly preserved, but are, as known at present, very rare. However, these lean spots can be made most productive of paleontologic results by careful search and by methods of preparation. Several years ago the number of lower Paleozoic fossils found in the Ozarks could almost be counted on one's fingers, but we now have in the National Museum, from this formerly almost barren spot, several hundred drawers of beautiful material.

Fortunately the preparation and methods of study of paleontologic material has progressed to such a point that a poor fossil is no longer a bugbear. A specimen may be considered inadequate for study because it is covered with refractory clay. The application of caustic potash solves this difficulty. Certain limestone bands in the New York Niagaran and Cayugan are crowded with fossils, although often few of the species can be determined because of a hard, clayey covering. In preparing some specimens for exhibition, the treatment with caustic of a single slab, about three inches wide and five inches long, enabled me to bring out over a hundred species on one surface alone, not including the ostracods and other microscopic organisms. How often will the present sea bottom furnish such results?