HAS THE EXTENT OF LAND SUEFACE BEEN INCREASING? 215 



Here we have, for the first time, a distinct recognition of the fact that the 

 continental masses have appended to them a border area which is indeed sub- 

 merged, but to so shght a depth that the portion thus covered by shallow 

 water really forms a part of the continent itself Slight oscillations of level 

 may therefore alternately cover and expose these border areas, as well as 

 the similarly situated low portions in the interior of the continent, without 

 changing in any essential degree the real relations of land to water surface 

 on the tJ-lobe considered as a whole. These changes of level which we know 

 to have taken place have often been of the greatest importance in the geo- 

 logical development of the land, while at the same time not essentially inter- 

 fering with the present outline and position of the oceans. 



Similar views to those cited above as having been enunciated by Dana and 

 Agassiz have quite recently been published by several distinguished European 

 geologists and physical geographers, among whom Professor A. Geikie and Dr. 

 W. B. Carpenter may be especially mentioned.* Professor Geikie thus sums 

 up the results, as formulated in his own mind, of tlie study of the sea bottom 

 as recorded in tlic work of the Challenger expedition : "' From all this evi- 

 dence we may legitimately conclude that the present land of the globe, 

 though formed in great measure of marine formations, has never lain luider 

 the deep sea ; but that its site must always have been near land. Even its 

 tluck marine limestones are the deposits of comparatively shallow water. 

 Whether or not any trace of aboriginal land may now be discoverable, the 

 characters of the most unequivocally marine formations bear emphatic tes- 

 timony to this proximity of a terrestrial surface. The present continental 

 ridges have probably always existed in some form, and as a corollary we 

 may infer that the present deep ocean basins likewise date from the re- 

 motest geological antiquit}^" t 



Since therefore it may with truth be stated that there is a strong body 

 of evidence and a marked unanimity of opinion among the most eminent 

 physical geographers and geologists in f;ivor of the idea of '• tbe permanence, 

 throughout all geological time, of what may be calle'l the frame-work of the 

 existing Continents, on the one hand, and the real Oceanic basins on the 

 other," — to use Dr. Carpenter's own words, — it appears equally proper to 



• See " Geographical Evolution," a lecture delivered before the Royal Geograjihical Society at the Evening 

 Meeting, March 24, 1S79 (Proe. E. G. S., New Series, Vol. I. p. 422), and the Address by Dr. Carpenter to which 

 reference has been previously made (unle, p. 210). 



t 1. c., p. 42S. 



