by Sedimentary Loading and, Recurrent Expansion. 487 



American Cordillera, the Appalachians, the Mountains of the 

 Caucasus, and the Urals. The question at once arises in the 

 mind, " Is this cause and effect? " If not, it is a coincidence 

 somewhat in the nature of a miracle. If any one example to 

 the contrary could be quoted, the argument of relation would 

 be weakened, certainly not disposed of, but, so far as present 

 knowledge extends, not one can be found. 



Sedimentary Deposits out of ivhicli Mountain-Ranges have been 

 built up extend over Vast Areas. 



The deposits out of which great mountain-ranges have been 

 elaborated by foldings, intrusions, and upheavals are not con- 

 fined to the ranges and their immediate neighbourhood, but 

 extend over vast areas. Speaking generally, modern geo- 

 logical investigation goes to prove that the thickest deposits 

 lie, or have lain, towards the axes of the chains, though they 

 may have been denuded from the actual axes*. Beyond the 



calls in question this principle, though it is admitted by nearly all geolo- 

 gists since Dr. James Hall established the fact as regards the Appalachians 

 in 1857. Quoting my words in the ' Origin,' " It is impossible to poiut to 

 a range of mountains which has been built up of old denuded rocks," he 

 completely misinterprets my meaning, which I had thought was plain 

 enough from the whole tenor of the work. To give an illustration in the 

 form of a prediction, I aver that uo mountain-range will ever be built up 

 out of any portion of the present land-area of Europe unless, and until, a 

 basin of deposition has been established, and a thick sedimentary series 

 deposited thereon. The old rocks may then be forced up along with the 

 new, and form a constituent part of such a range. Unfortunately, as regards 

 the Himalaya, information is meagre ; but the granitic axes pointed to by 

 Mr. Middlemiss as forming the highest peaks of the Himalaya are just 

 what are required by my theory. 



* Mr. Arthur Winslow, State Geologist of Missouri, in a paper just 

 published in the ' Bulletin ' of the Geological Society of America, entitled 

 "The Geotectonic and Physiographic Geology of Western Arkansas" 

 (vol. ii. pp. 225-242), has applied the principles enunciated in the 'Origin 

 of Mountain-Ranges ' to the explanation of an area in the Western part 

 of the State tributary to the Arkansas River, 100 miles long in an East 

 and West direction by 50 miles broad in a North and South direction. It 

 is shown in an admirably concise and clear manner that the system of 

 parallel interlocking anticlines and synclines having a general axial direc- 

 tion East and West is essentially Appalachian in character; that the 

 Carboniferous strata of which they are composed increases in thickness 

 from Missouri southwards into Arkansas; that the lateral movement has 

 come from the South, and that the thickest strata are the most flexed. 

 Mr. Winslow shows — a point that I have strongly insisted upon as cha- 

 racteristic of anticlines — that these geological features are elongated 

 canoe-shaped domes having quaquaversal dips. He considers that the 

 expansion of the lower layers of rock produced by the rising of the iso- 

 geotherms and their consequent protrusion in the form of anticlinal cores 

 has fractured the apices of the arches, and thus exposed the upper layers 



