JO THE BUILDING OF AN ISLAND. 



CHAPTER IX. 



Connection of the foregoing with the Physical Geography 



OF the Island. 



From our study of the stages through which our island has passed it seems 

 to be plain that its present form, both generally and in detail, must depend on 

 three things : firstly, the quality of the materials of which it is composed, next 

 the mode of its elevation, and thirdly, the mode of its sculpturing. The infor- 

 mation which we have been able to obtain on these subjects wnll help us to 

 form some conception of the way in which the existing physical features of the 

 island have originated. 



In considering the elevation which followed the deposition of the lime- 

 stones, which we mav call the recent elevation, as distinguished from the earlier 

 elevation which followed the deposition of the blue-beach rocks, we see from the 

 form of the island that the main movement has been from about north-by-west. 

 In the Western Ohlong the arrangement of the limestone strata, as well as the 

 surface form, shows us that only one main wave of the earth's crust has been 

 produced here, namely, that which has resulted in the forming of the northern 

 chain of hills. When we pass to the Eastern Triangle we find a different con- 

 dition. Here it appears necessarv to assume that there have been two waves, 

 the northern wave being shown in Buck Island and the neighbouring bank, 

 the southern and more important wave in the East End range of hills. If 

 layers of limestone now covered the Hanks of this range as they cover the 

 southern flank of the northern hills, we should probably see these layers slop- 

 ing away on ecxch side of the range, thus revealing the second or southern wave 

 form which we assume to have been the cause of its formation. 



The fact that the hills in the Eastern range arc seen to form three divi- 

 sions appears to be good evidence of two cross elevations, such as are found in 

 the central and west parts of the island, as revealed there by the dips of the 

 strata of the newer formation, and which would in all likelihood be similarly 

 revealed in the east, if the limestone now existed there. The crosscut through 

 the Christiansted Hills known as Spring Gut originated most likely in a split at 

 the top of the arch formed by these hills as they rose from the sea, or possibly 

 in a great north and south fault across the strata. It is a striking feature in 

 the local geography, and, as already noted, the " saddle " which it forms is 

 recognized as a well-known landmark for vessels arriving at the port of Chris- 

 tiansted. 



The Neck shows a veritable break in the structure of the island, as may be 

 seen by the deep water forming a bay opposite to it, as well as by the existence 

 of the synclinal arrangement of the limestone rocks of the land. In the low 

 hills which at the back of the Princess Plain border the Central Slope the dips 

 are to southeast and southwest, so that there seems to be no evidence of these 

 beds forming an arch going over to northeast, unless, indeed, such evidence is 

 presented in the small Cay in Christiansted Harbour, which is entirely com- 



