20 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



the Nassau Range and the next range on the Grantstown road. There 

 we find the seolian rocks of the surface coated with a hard ringing layer, 

 and modified to a great extent by the intercalation of amygdules of 

 red earth, which give to the rocks the appearance of an indistinct 

 conglomerate. 



At the foot of Nassau Street, twelve to fifteen feet above high -water 

 mark, the vertical wall (ten feet high) of the back of the quarry also 

 plainly showed lines of seolian deposit. On the way up the street there 

 are other quarries which have been abandoned, and excavations for 

 buildings showing the same structure. The quarries at the top of 

 Nassau Street are being worked, and fine vertical faces could be exam- 

 ined there fully twenty feet in height, which showed on the whole face 

 the same aeolian structure so plainly seen at the foot of the same street, 

 and at some other points of a still lower level, below high-water mark. 

 The whole of the ridge forming the first hill back of the har]Dor of 

 Nassau is evidently of seolian formation. Its highest point is about one 

 hundred feet. 



To the eastward of Fort Fincastle there are other old quarries, the 

 exposures showing the irregular lines of wind-blown deposits. Wher- 

 ever streets have been cut through the hillside as trenches, the same 

 lines are visible on the faces of the side slopes. The seolian rock is used 

 as building material throughout the Bahama Islands. It is either quar- 

 ried from the surface in rough blocks from accessible faces, or regularly 

 quarried, as at Nassau and Green Turtle Cay, by cutting narrow vertical 

 channels five to six feet in the face of the vertical cliff' exposui'es. A 

 similar cut is made parallel to the face. The blocks thus laid off are 

 then sawed in columns, and these in their turn sawed into blocks of 

 the size wanted for building purposes. Imbedded in the rock faces of 

 this quarry, and in the fragments scattered about, we found a number 

 of land shells, quite similar to those still living. Mr. Dall has kindly 

 prepared for the Bulletin a short account of the species collected. 



Through the mass of the exposures tubes were scattered irregularly, 

 formed from the decayed roots of bushes, grasses, and other plants which 

 covered parts of the sand dunes while they were forming. 



To the westward of Nassau the shore of New Providence is marked 

 by a succession of beaches and seolian rock outcrops, and outlying caA's, 

 which once must have been short lines of hills more or less parallel to 

 the principal hills on the north side of New Providence. They were 

 separated from one another by low wooded flats, very similar to those 

 now stretching at the base of the existing hills, but which by subsidence 



