28 THE BUILDING OF AN ISLAND. 



often of considerable thickness. The presence of this covering makes it im- 

 possible to mark the boundary of the limestone formation across the plain with 

 anv approach to accuracy, so that the line laid down in the map has in that 

 part very little practical value. If it were required, for instance, to know how 

 far the marl extends under the debris northwards, so as to get at it for agri- 

 cultural purposes, it would be necessary to decide the point bv borings. Some 

 years ago a boring for a well was made near the Bethlehem Works, to the 

 north of the Centre-line Road, and after a few feet of debris, a thickness of 150 

 feet of marl was passed through; hence we are safe in carrying the line north 

 of the Bethlehem Works. A few hints further west enable us to carry it 

 along the north side of the Centre-line Road past Lower Concordia, and then 

 northwards l)ack of Frederiksted to the coast. In contrast with the uncer- 

 tainty as to the boundary over this plain, we find that the boundary around the 

 Central Slope is not difficult to fi.x and will be found to be verv ncarlv as laid 

 down in the map. 



The plain country of the southwest affords only a few exhibitions of the 

 marl rocks in low cliffs (or vertical banks) on the seashore, and in shallow road- 

 cuttings here and there. At Betty's Hope and some other places these banks 

 contain a great number of verv hard limestone nodules of irregular forms, 

 apparently concretions or, perhaps in some cases, concretions that have been 

 partly rounded by water. The concretions may be seen in the shallow road- 

 cuttings and in the banks along the shore at Betty's Hope. At Long Point 

 the rocks contain a great number of impressions both of shells and corals, and 

 in some places the fossils themselves have been left. Neither in these cliffs, 

 although some parts are over 20 ft. in height, nor in the few shallow road- 

 cuttings in this part of the country do the rocks show any distinct stratification, 

 and it may be that they form a thick mass nearly or quite horizontal. 



At Frederiksted we have the remarkable limestone already described. 

 The quarries are to the east of the town ; the strata are somewhat irregular 

 and much broken; they dip away at a rather high angle (about 2~, degrees) to 

 the west. Considering that the island ends abruptly along its western shore, 

 this steep dip to the west is very suggestive. It would appear that the lifting 

 force which brought up these rocks was greatest somewhere to the east of the 

 town. Where is that line of elevation, that anticlinal axis? It probably 

 stretches from northeast to southwest through the northwest hills, and is con- 

 tinued along the spur that comes down towards Concordia, ending in the long 

 point (Sandy Point) which stretches out at the southwest extremity of the 

 island. This view is strengthened by the geography of the marls in this part 

 of the island, namelv, their lying along the south coast on the east side of 

 the supposed anticlinal, and along the west coast on the west side of it, and 

 it is also confirmed by the flow of the surface waters from the northwestern 

 hills, namely, towards the south on their southern side and towards the west 

 on their western side. 



At the entrance to the town of Frederiksted there are some beds of lime- 



