448 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



the "Conodonts" in the Cambrian glauconitic sands and the 

 fish remains in the Old Red Sandstone of Livland. F. Schmidt 

 wrote a monograph of the Silurian Trilobites in this area, and 

 afterwards contributed a masterly exposition of the Silurian 

 rocks in the Baltic area, dividing them into a palaeontological 

 sequence which is unsurpassed in the accuracy of its detail 

 (1881-94). Several important memoirs by Stache have de- 

 monstrated the presence of Silurian deposits in the Alps, 

 with much wider extension than had previously been surmised. 



C. Devonian System. While the controversy about the Cam- 

 brian and Silurian systems was still engaging the attention of 

 British geologists, the Continental geologists were applying them- 

 selves with vigour to the elucidation of the "Transitional Rocks" 

 in accordance with the new insight which Murchison's writings 

 had shed upon the Palaeozoic succession. Friedrich Roemer 

 endeavoured to arrive at some clearer comprehension of the 

 stratigraphical relations in the Harz mountains by a strict 

 palaeontological method. In 1843 he published a monograph 

 on the fossils of the Harz mountains. Beginning his observa- 

 tions at the north-western area of the Harz, he explained the 

 I berg limestone, the Rammelsberg shales, and succeeding 

 strata as Devonian ; the Harzburg and Osterode greenstone, 

 together with the surrounding strata and the limestone mass of 

 Elbingerode, as Upper Silurian ; the adjoining strata on the 

 east and as far as Andreasberg as Lower Silurian ; and the 

 whole of the mountain-system farther east as Cambrian. 



Roemer added in subsequent memoirs several valuable con- 

 tributions to the palaeontological data of the Harz, and verified 

 his general statement of the stratigraphy by further details. 



As early as 1837, Beyrich had published a number of 

 observations on the fossils of the Eifel, Paffrath, and Nassau 

 limestone. He pointed out their differences from those of the 

 Carboniferous limestone, and showed that the larger portion of 

 the greywacke in the Rhine provinces is older than the lime- 

 stone of the Eifel and in Nassau, but that above the Nassau 

 limestone there is a thick development of greywackes and 

 slates with Posidonomya Becheri, whose fossils agree with 

 those of the Upper quartz schists in the Liege province. 



The Palaeozoic formations of the Rhineland were made the 

 subject of an important monograph by Ferdinand Roemer in 

 1844. This geologist divided the "Transitional Series" into 



