Yol. 57.] PHYSICAL DEVELOPMENT OF GTrADELOUPE. 507 



studies of Pierre Duchassaing,^ constitutes our principal knowledge 

 of the Tertiary formations of Guadeloupe, and will be referred to in 

 the following pages. 



II. Situatio:n^ and Physical Characteristics. 



The nearest point of Grande Terre is 36 miles from Antigua, 

 from which it is separated b}^ a broad depression in the Antilleau 

 plateau, submerged to a depth of about 20u0 feet, out of which 

 rises an intermediate island now sunk to a depth of 300 feet." 

 This submarine ridge is dissected b}' channels and indeijtations, 

 reaching to depths between 2^:00 and 3000 feet below sea-level. 

 The characteristics of the drowned valle3^s of the Guadeloupe 

 archipelago will be considered under the heading of erosion-features. 

 The southern part of the group is separated from Dominica by a 

 submarine depression about 17 miles wide, having a depth of 

 2100 feet, but this is further dissected so that the indentation, 

 south of The Saints, is found to reach a depth of 3294- feet. 



Grande Terre has a triangular form, composed of three lobes. 

 It is about 18 miles from north to south, with a somewhat greater 

 transverse diameter ; but it is so deeply indented as to reduce the 

 area to 217 square miles. It is an undulating limestone-country, 

 the northern lobe being separated from the more southern portion of 

 the island by a plain or valley, reaching to a width of 2 miles, and 

 of an elevation generally less than 50 feet above the sea. This 

 extends north of west from Moule across the island. IS'orth 

 of the depression, from near Port Louis extending eastward, is 

 a limestone-escarpment, crossing the island, and rising 150 feet 

 above the low country, or 200 feet above the sea. One point on 

 this northern plateau rises to 279 feet. South of the great 

 depression, the central portion of the island is broken into valleys 

 and hills, one point rising to 354 feet. Thus there is a general 

 resemblance in Guadeloupe, even as to height, with that district 

 of x^Lutigua which is underlain by the White Limestones. Xatural 

 rock-exposures are relativelj^ few, as the surface is generally 

 covered deeply with soil. 



Guadeloupe proper has the form of an ellipse, with a length 

 of 28 miles, a breadth of 11 miles, and an area of 365 square miles. 

 The high mountain-ridge traversing it is surmounted by four volcanic 

 cones, the highest of which is 4868 feet. The descent of the 

 mountains to the west is rapid, leaving little or no low land 

 between their base and the coast. Even the delta-flats at the end 

 of the short steep valleys are insignificant. However, the high 



1 Bull Soc. Geol. France, ser. 2, vol. iv (1847) p. "1093. & ibid, vol.xii (1855) 



p. 753. ' • ' - - ' '• -— -- -1^^ A :u...:... ,.„ 



A. 



also J-- - - „ ^, ^ ^ 



in 1848-59 : but I have not seen the two last-mentioned works. 



- See U.S. Hydrographic Chart No. 40, or the corresponding British 

 Admiralty Chart. 



2m2 



