120 NATURAL SCIENCE [February 



be a physical impossibility for so complex an area, composed of beds 

 of such different compositions, hardness, and dip, to have been up- 

 raised without any relative displacement of the different parts. 

 Therefore, argues Suess, as the land cannot have been upraised, the 

 sea level must have fallen. That alternations in the position of land 

 and water are due to movements of the land is one of the funda- 

 mental principles of Lyellism. Suess, therefore, proceeds to enquire 

 whether geological evidence supports Lyell's view, or whether there 

 is any proof of actual variation in the form or position of the 

 hydrosphere, which would locally alter the height of its upper sur- 

 face. The introductory chapter states the conclusions of the 

 geodesists as to the existing inequalities in the sea surface. Then 

 he asks is there any historical evidence as to the flooding of land 

 areas without subsidence of the land ? He tells again the Chaldean 

 story of the Noachian deluge as revealed by the Daily Telegraph 

 tablets ; he concludes that the absence of similar traditions in 

 Egypt proves that the flood was local, and he shows that the whole 

 of the facts in the Chaldean version are explicable by a flooding of 

 the Mesopotamian plain caused by earthquakes in the Persian 

 Gulf. The great shock was, no doubt, preceded by preliminary 

 shocks, which may have acted as a warning to the wise, and the 

 great flood may have been increased by an accompanying cyclone. 

 The author then proceeds to discuss some of the principles of 

 dynamical geology, in chapters on the forces that move the land 

 masses. He first considers earthquakes, and describes four typical 

 earthquake areas. He concludes that earth movements are of two 

 kinds ; foldings produced by tangential thrusts, as in mountain 

 building and subsidences produced by radial contraction. The 

 uplift of large, uncontorted superficial areas he declines to accept. 

 He discusses the oft-quoted assertion as to the elevation of the 

 South American coast by earthquakes, and denies that the evidence 

 supports that conclusion. He is here opposed to Darwin, so he 

 goes into the case fully and appears to prove his contention. In 

 order to get light as to the internal nature of the earth, he then 

 turns to vulcanism. He describes the laccolitic habit of acid lavas 

 and the broad flows and sheets of basic lavas, and proposes 

 the term ' batholites ' i for those great masses of granitic rocks, 

 which may perhaps be most briefly explained as plutonic laccolites, 

 in which the igneous rock occupies a pre-existing cavity which it 

 did not itself form. The existence of such cavities must be inferred 

 in order to explain vertical subsidences. Hence, from a study 

 of a series of typical earthquakes, geognostic dislocations, and vol- 



1 An illustration of the extent to which Suess' work has been neglected in England is 

 shown by the fact that, in the Geological Society's last discussion on the nature of the 

 Dartmoor granite, though the question of its laccolitic origin was considered, the term 

 batholite was not mentioned in the report. 



