EXPLANATION OF THE PLATES. 



PLATES XVIIL XIX. XX. XXI & XXII. 



Illustrate Mr. De la Beche's paper on the Geology of Jamaica. 



Plate XVIIL 

 A map of part of Jamaica. 



Plate XIX. 



Fig. 1. Section of the strata at St. George's Gap. 



Fig. 2. Section from the sea near Kingston to Forster's Cove, St. Mary's. 



Fig. 3. Section from Old Harbour to Luidas Vale. 



Fig. 4. Section from the sea to Catherine's Peak. 



Plate XX. 

 View of a natural bridge near Mount Olive, St. Thomas-in-the-Vale. 



Plate XXI. 

 Represents a cast of part of a gigantic cerithiura, from the yellowish white limestone. 



Plate XXIl. 

 Panoramic view from Strawberry Hill, one of the St. Andrew's Mountains. 



PLATES XXIII. XXIV. & XXV. 



Illustrate Mr. Scrope's paper on the Geology of the Ponza Isles. 



Plate XXIII. 

 Map of the volcanic districts between Rome and Naples ; and, 

 Map of the trachytic group of the Ponza Isles. 



Plate XXIV. 



Fig. 1. View of the Island of Ponza from the East side, about four miles distance. 



Fig. 2. Semicircular cove called Chiaja di Luna, Isle of Ponza, S.W. side. 



Fig. 3. Montagna della Guardia from the South. 



Fig. 4. Rock of contorted and globiform pitchstone, Chiaja di Luna, Isle of Ponza. 



Plate XXV. 



Figs. I, 2 & 4. Views of the eastern side of Ponza. 



Fig. 3. Rock of columnar trachyte near the N. E. point of Palmarola. 



Fig. 5. Zannone seen from the south. 



