50 Prof. A. G. Hdghom—Life of Prof. A. E. T'drnebohm. 



until 1873. Several maps (1 : 50,000), with descriptions, were 

 published during these years. Noteworthy among them are the 

 sheets comprising a great part of the Pre-Cambrian complex, generally 

 known as the Dal Formation, which lies west of Lake Wenern. 

 Beneath this Dal Formation, and separated from it by a great 

 unconforinit}', comes an Archaean complex, the Araal Complex, in 

 which Tornebohm, as far back as 1870, recognized volcanic tuffs and 

 beds of conglomerate ; the latter are probably the first described true 

 Archaean conglomerates. 



Besides mapping in different parts of Middle Sweden, Tornebohm 

 at this stage of his career entered the highlands and dealt with their 

 stratigraphy in two important memoirs. The first of these memoirs 

 gave a cross section of the mountain range from Ostersund to Levanger 

 (1872), and the second, tfber die Geognosie des Schwedischen Uoch- 

 gehirges (187.3), was accompanied by a survey map of a considerable 

 part of the highlands. In these papers Tornebohm stated that the 

 fossiliferous Cambrian and Silurian rocks at the eastern border of the 

 mountain range were covered by thick complexes of mica-schists, 

 gneisses, amphibolites, and quartzites. The stratigraphy was regarded 

 as normal and the rock complexes were divided up into a lower series, 

 the Seve Group, and an upper series, the Koli Group, both regarded as 

 younger than the underlying fossiliferous Silurian. Some geologists 

 in Sweden opposed this interpretation, and in Norway the researches 

 of Kjerulf could not be brought into harmony with it. On the other 

 hand, later surveys reaffirmed the general correctness of Tornebohm's 

 observations in regard, that is, to the order of superposition of the 

 strata in the districts examined by himself. 



But Tornebohm had no opportunity to ])ursue his researches in the 

 mountains for some years to come. In 1873 he left his post as State 

 Geologist, and partly for purposes of study, partly for considerations 

 of health, undertook a journey to Italy, Austria, and Germany. He 

 stayed for a time in Leipzig, where, under the guidance of Professor 

 Zirkel, he learned microscopic petrography. 



After his return home Tornebohm surveyed several mining districts 

 in Middle Sweden, and in 1878 was appointed Professor of Mineralogy 

 and Geology at the Technical High School of Stockholm; this post, 

 in 1897, he exchanged for the directorship of the Geological Survey. 



In the seventies and eighties Tornebohm published a great number 

 of peti'ographical memoirs, as, for instance, his fundamental Sydematic 

 Research on the Diabases and Gahhros (1877), and his descriptions of 

 zircon, epidote, scapolite, and calcite as constituents of igneous rocks. 

 He also examined several rock types, new to science, namely, cancrinite- 

 syenite, alnoite, and somewhat later (1907) catapleite-syenite, with 

 associated rocks. His study Zur Petrographie des Portlandscements 

 (1905) attracted much attention. 



Besides these purely petrographical papers, Tornebohm has left rich 

 material of a similar character in the form of petrographical observations 

 dispersed through his more strictly geological works. For theoretical 

 problems of petrology he had but little interest, and accordingly did 

 not enter mucli into sucli matters. The breadth of his researches in 

 petrography is illustrated not only by his writings, but also by his fine 



