22 Capt. F. W. Hutton — On the Formation of Mountains. 



Explanation of Fi&ubes Illustrating Papeb, on Isle op Thanet Chalk. 



Fig. 1. — Sketch-map of Isle of Thanet. 

 Fig. 2. — Cliif Section from Birchington to Kingsgate. 

 Fig. 3. — Cliff Section from Kingsgate to Pegwell. 



The shaded part represents the Ammonite Bed, bounded on the upper edge by the 

 guiding line of flints. 



The Three-inch band of flints. 



The columnar band of flints, 



I. North Foreland. 

 m. Joss Stairs. 

 n. White Ness. 

 o. Fore Ness. 



p. First Gangway, east of large Flag- 

 staff. 

 Jetty-end of Cliff, Margate. 



-}- + -t- + + + -fH--l- + -f-H- 



a. Tertiary bed. 



b. Pegwell fault at which Tertiaries 



begin, 



c. A point a little east of Landing-stage, 



Pegwell. Lowest point of chalk, 



d. West Cliff Terrace. 



e. Eamsgate Harbour, 

 /. Various faults. 

 g. Dumpton Stairs. 



h. Dumpton Point. 

 i. Broadstairs. 

 k. Stone Stairs. 



P, Explained in text. 



r. Infirmary end of Cliff, Margate, 



s. Marsh Bay. 



t. Apple Bay. 



zi. Birchington. 



Table showing Distribution gw Ammonites in the Section. 



Points marked in 



Distance. 



Number of 



Sketch-map. 



Miles. 



Specimens. 



u io s 



2^ 



27 



s to r 



IX 



17 



r i,Q q 



u 



No cliff. 



-q to p 



1 



24 



p to I 



2^ 



21 



I to c 



4X 



None found. 



■c to b 



% 



4 





13 



93 



VII. — On the Fobmation of Mountains. A Eepit to the Key, 



0. Fisher. 

 By Capt. F. W. Hutton, F.G.S. 



T was with great interest that I read in the Geological Magazine, 

 Vol. X. for June, 1873, the Eev. 0. Fisher's able paper on the 

 Formation of Mountains ; and although I cannot altogether agree to 

 his reasoning, I have to thank him for re-calculating, more correctly 

 no doubt than I have done, my table of the altitude of domes, and 

 also for explaining several points which I had not clearly conceived 

 before. Nevertheless, I think that I shall be able to show that his 

 arguments against the theory that I have advocated ^ are not well 

 founded. 



For the sake of conciseness, I will, in what follows, call the theory 

 that Mr. Fisher advocates the " Contraction theory," meaning thereby 

 the theory of the formation of mountains by the secular cooling and 

 contraction of the earth ; while I will call the theory that I advocate 



1 On the Phenomena of Elevation and Subsidence, Phil. Mag., Dec. 1872, and on 

 the Formation of Mountains, Geol. Mag,, April, 1873, p. 166. 



