68 



GEOLOGY. 



and beyond which it could never pass, would be the length of the land 

 area in the direction of the valley's axis. In width, a valley is increased 



Fig. 48. — Same as Fig. 47, with the valleys more developed. The dotted line repre- 

 sents the original outline of the island. Its area is being extended by deposition 

 everywhere, but most at the debouchures of the streams. 



Fig. 49. — A later stage of the island shown in Fig. 48. 



