AGASSIZ: BAHAMAS. 57 



bars are all flourishing, and consist mainly of heads of Astrseans and 

 of MsEaudringe. 



The shore lines of Orange Cay, as well as the adjoining isolated rocks, 

 are all eaten away at the base, the surface being completely pitted and 

 honeycombed; this small cay, with the scattered isolated rocks extending 

 to Riding liocks, being all that is left of the western part of the great 

 Andros Island land. Riding Rocks are found, like Orange Cay, to be 

 composed of the same kind of aeolian rock. Masses of corals are flour- 

 ishing, forming great patches more or less disconnected on the face of 

 the bank towards the Gulf Stream, extending to fifteen or seventeen 

 fathoms of water. Astra^ans, Maeandriuce, Millepores, and Madrepores 

 extend all the way to Gun Cay. Nowhere perhaps oji the Bahamas is 

 it more obvious that the existing bars of corals found along the sea face 

 of the nearly continuous bank throughout the Bahamas have had noth- 

 ing to do with the formation of the cays and rocks on the west side of 

 the Andros Bank. The coral masses are merely surface growths as it 

 were upon the banks, which owe their building up to entirely different 

 causes and to a state of things which has long passed away. 



From Riding Rocks to Gun Cay a series of isolated patches, rocks, 

 and islets, all of the same character, sometimes in two or more parallel 

 rows, run north on the edge of the bank ; these are flanked on the west- 

 ward by very flourishing patches of corals growing close together, and 

 extending on the sea face of the bank into about seventeen fathoms 

 of water. These rocks and islets are comparatively less barren as 

 we go north. The remnants of the former land also increase in num- 

 ber as we approach Gun Cay, and become still more numerous and large 

 with the Beminis and the adjacent rocks and islets. On the southern 

 end of South Cat Cay there is a considerable peolian hill, covered with 

 vegetation similar to that of other islands on the east face of the 

 bank. North Cat Cay has a grove of cocoanut palms and low bushes. 

 The sea face shore lines of this and South Cat Cay are protected against 

 the action of the sea by lines of outlying rocks, and are thus less affected 

 by the wearing action of the prevailing winds. South Cat Cay is high 

 enough to have, near the middle of the north end, a line of low vertical 

 cliffs, both the Cat Cays being somewhat higher than Gun Cay. 



