260 APPENDIX. 



terized fringing-reefs are coloured red. — Westward of long. 

 77° 30', on the northern side of Cuba, a great bank com- 

 mences, which extends along the coast for nearly four degrees 

 of longitude. In its structure, and in the ' cays,' or low islands 

 on its edge, there is a marked correspondence (as observed by 

 Humboldt, Pers. Narr. vol. vii. p. 88) between it and the great 

 Bahama and Sal Banks, which lie directly in front. Hence 

 one is led to attribute the same origin to all these banks ; 

 namely, the accumulation of sediment, conjoined with an 

 elevatory movement, and the growth of coral on their outer 

 edges. The parts which are fringed by living reefs are 

 coloured red. — Westward of these banks, there is a portion 

 of coast apparently without reefs, except in the harbours, the 

 shores of which seem in the published plans to be fringed. — 

 The Colorado Shoals (see Captain Owen's charts), and the low 

 land at the western end of Cuba, correspond as closely in 

 relative position and structure to the banks at the extreme 

 point of Florida, as the banks above described on the north 

 side of Cuba, do to the Bahamas. The depth within the islets 

 and reefs on the outer edge of the Colorados, is generally be- 

 tween two and three fathoms, increasing to 12 fathoms in the 

 southern part, where the bank becomes nearly open, without 

 islets or coral-reefs ; the portions which are fringed are coloured 

 red. — The southern shore of Cuba is deeply concave, and the in- 

 cluded space is filled up with mud and sand banks, low islands 

 and coral-reefs. Between the mountainous Isle of Pines and the 

 southern shore of Cuba, the general depth is only between two 

 and three fathoms ; and in this part, small islands, formed 

 of fragmentary rocks and broken madrepores (Humboldt, 

 Pers. Narr. vol. vii. pp. 51, 86 to 90, 291, 309, 320), rise 

 abruptly, and just reach the surface of the sea. From some 

 expressions used in the Columbian Navigator (vol. i. pt. ii. 

 p. 94), it appears that considerable spaces along the outer 

 coast of southern Cuba are bounded by cliffs of coral-rock, 

 formed probably by the upheaval of coral-reefs and sand- 



