82 



SCIENCE. 



[N. S. Vol. XII. No. 290. 



Hartz, the Erzgebirge and Thuringia ; and 

 speaking as I do, in a lecture room of our 

 oldest American School of Mines, it is a 

 special pleasure to note this connection and 

 to render to the ancient art of mining — the 

 real mother of geological science — her just 

 due. There is no doubt in my mind that 

 the keen observation of miners had con- 

 vinced them that there was some regular 

 succession in the rocks, long before this 

 principle found accurate, scientific expres- 

 sion in printed form ; but, so far as we know? 

 it was first formally stated by Johannes 

 Gottlob Lehmann in connection with some 

 profiles or cross-sections of the Hartz and 

 the Erzgebirge, which he prepared about 

 the middle of the last century. Lehmann, 

 who was a mining official under the Prus- 

 sian government, had observed that flat and 

 undisturbed beds rested upon earlier tilted 

 beds and upon crystalline rocks, both of 

 which latter he assumed as his original 

 base but with whose relations he did not 

 concern himself. A few years later in 

 Thuringia, George Christian Fuchsel dealt 

 in a tectonic way with the Coal Measures, 

 the Permian and the later systems, but as 

 we all know it was not until the close of the 

 eighteenth century that William Smith 

 made known the use of type fossils in Eng- 

 lish geology, nor was it until 1808 that 

 Cuvier and Brogniart, working upon the 

 extremely regular deposits of the Paris 

 basin, established for France if not for the 

 world the use of fossils on a large scale. 

 They brought out a definite sj'stem, which 

 anticipated by a few years the issue of 

 William Smith's famous map of England. 



It was natural that these results should 

 be attained in regions of simple and easily 

 deciphered stratigraphy, and of relatively 

 modern beds. Taught and inspired by this 

 pioneer work, the geologists of the quarter 

 century that followed interpreted the Tei*- 

 tiary and Mesozoic strata, wherever fairly 

 flat and undisturbed. Even the Coal Meas- 



ures were studied and placed in their true 

 position, but except in New York, where 

 the older series are likewise flat and undis- 

 turbed, the lower lying Paleozoic remained 

 a sealed book. It even seemed a rash and 

 foolhardj' undertaking when the two Eng- 

 lish geologists, Sedgwick and Murchison 

 attacked the hills and mountains of Wales 

 and Devonshire some 75 years ago. The 

 structural problems which this region pre- 

 sented were esteemed too complex and too 

 difficult to justify the expenditure of effort 

 upon them. Sedgwick and Murchison, 

 however, found the clues and bj'^ careful 

 work finally classified the strata and despite 

 faults, folds and moderate metamorphism, 

 placed them in their true position. These 

 observations opened up for investigation 

 the whole Paleozoic and set the pace as well 

 as laid out the course for stratigraphical 

 geologists until a decade or two since. So 

 much has now been accomplished, how- 

 ever, that even in regions of very violent 

 change, the problems of the Paleozoic may 

 now be considered to be in a high degree 

 solved, and the range of work upon its 

 series and stages has become chiefly faunal 

 and biological. 



But the course of geological investigation 

 has tended ever downward to lower and 

 lower horizons. It may be said that in re- 

 cent years the chief problems of strati- 

 graphic interest have involved that tempt- 

 ing yet elusive series of sediments that lies 

 below the limits of well-preserved and 

 recognizable fossils. The remains and 

 organisms, which are so abundant and use- 

 ful in the Paleozoic, disappear in the most 

 remarkable way as we go below the Cam- 

 brian, and yet there are few geologists who 

 do not confidentl}' believe that in some cor- 

 ner of the world, not yet fully explored, 

 they will be found in satisfactory abun- 

 dance. Traces are of course already known. 

 Walcott, in the West ; Matthew, in the mar- 

 itime provinces ; and Barrois, in Britany, 



