AGASSIZ : BAHAMAS. 19 



harbor owes its existence in part to the general subsidence of this part 

 of the Bahamas, which has sunk the valley between Hog Island and 

 Nassau Hill as much as seventeen feet below low-water mark ; while the 

 Grantstown plain to the south of Nassau Hill (Plate XVI.), extending 

 to the next range, is still a few feet above high-water mark. A slight 

 subsidence would separate Nassau Hill from the rest of New Provi- 

 dence and form a second range like Hog Island to the north of a large 

 bay (Grantstown plain), cutting off the southern part of the island. 



This ridge extends westward beyond Fort Charlotte from the point on 

 which Fort Montague is built. From the Caves to the western entrance 

 of Nassau Harbor the north shore of New Providence is formed by a line 

 of hills running nearly parallel with it, and making the north side of the 

 basin of Lake Cunningham. A broad valley stretches between it and 

 the range of hills extending from Fort Charlotte to Fort Montague, 

 the valley gradually opening out as we go westward from the Cave 

 Point. The shore line itself is a long series of seolian rock sand beaches 

 (Plate XVIII. ), separated by an occasional rocky projection forming low 

 cliffs. 



The part of the island adjoining the north shore is covered principally 

 by shrubs and trees. The flats at the foot of the hills are cultivated, 

 and covei'ed with sisal or cocoanut plantations. 



The Queen's Stairway presents one of the finest sections of the seolian 

 rocks of Nassau (Plate XV.) ; not only does the road leading up to its 

 base pass through cuts of seolian rocks ranging from five to fifteen feet, 

 but the so called Stairway itself is a succession of walls showing an ex- 

 posure of fully sixty feet of seolian rock. This seolian rock when first 

 exposed to the air is comparatively soft, but becomes quite hard after 

 exposure to the action of the atmosphere. 



Immediately behind the Queen's Stairway, on the southern slope of 

 the Nassau Piange, there is a fine quarry, one of a series which begins at 

 Nassau Street and runs along the top of the range to the eastward of the 

 Stairway. About one third of the way up the hill there is also a large 

 abandoned quarry, showing the structure of the seolian rock. A few 

 smaller abandoned quarries are found near the base of the hill, in which 

 the exposed faces differ in no wise in character from those of the other 

 parts of the hill. The same was found to be the case in the -street 

 leading from the main street to the Queen's Quarry, the nature of the 

 exposed faces being everywhere the same. 



The seolian rock faces as exposed in the quarries are in striking con- 

 trast with the harder rock surfaces exposed in the low ground between 



