INTRODUCTION. 125 



molten mass in this way ; granite, porphyry, trap, basalt, and 

 similar rocks were pressed up by subterranean heat, but did 

 not reach the surface ; they were intercalated as subterranean 

 eruptive masses partially between pre-existing sedimentary 

 rocks, or they spread as extensive sheets of rock-magma on 

 the ocean-floor. Notwithstanding the strong support given to 

 Hutton's theory by his friends and adherents, Hall, Playfair, 

 and Watt, the theory of the Scottish genius found little recog- 

 nition in his life-time. The Plutonic doctrines were slow to 

 plant their roots in geological literature, and it was not until 

 the third decade of the nineteenth century that they were 

 universally accepted. 



Palceontology. The first two decades of the nineteenth 

 century, which were remarkable for the great advances in 

 petrography, were less fruitful in the domain of palaeontology. 

 In Germany, the Wernerian school was almost wholly absorbed 

 in the study of rocks, and the petrified remains of plants and 

 animals were in a measure neglected. The splendid work of 

 Walch and Knorr had been followed by Schroter's Introduction 

 to the Knowledge of Rocks and Fossils, the value of which rested 

 chiefly upon its bibliographical merits (1774-84). 



The famous Gottingen zoologist, Blumenbach, published in 

 1803 and 1816 two short treatises on fossils. He sub-divided 

 fossils into four groups: (i) Fossils identical with existing 

 species still represented in the same localities where the fossil 

 forms existed ; (2) fossils identical with existing species, but 

 not with those at present inhabiting the particular localities 

 where the fossils occur; (3) fossils indicative of some great 

 climatic change in the localities where they are found e.g., 

 cave-lion, rhinoceros, etc., which resemble but are not identical 

 with living species ; (4) marine fossils belonging to extinct 

 species, and showing that the earth was once covered by the 

 ocean. 



It seems surprising that such crude and superficial concep- 

 tions of fossil groups should have been formulated by a 

 zoologist of the reputation of Blumenbach, yet such was his 

 fame that his opinions received far more attention than they 

 deserved. 



Baron Ernst von Schlotheim (1764-1832) was one of the few 

 adherents of Werner who devoted himself to the study of 

 fossils. His first work, published at Gotha in 1804, was a 



