690 MR. R. J. LECHMERE GtJtPY ON THE GEOLOGY [Nov. I9H, 



largely given rise to the physical features of the island. But, in 

 reality, the physical features of Antigua are mainly due to the 

 causes which I am about to mention, and denudation has played 

 quite a subordinate part in shaping the features of the island. 

 I have seen the effects of erosion, marine and fluvial, in many parts 

 of the world (for example, in New Zealand, Switzerland, Italy, etc., 

 not to mention the coasts of England and Wales) ; but I could not 

 assimilate the features of Antigua to any of them. The Bocas or 

 channels at the entrance of the Gulf of Paria are good examples 

 of submerged valleys, which have been immensely enlarged by 

 marine erosion. Near them are sunken valleys which have not 

 been so enlarged. But none of them in any way resemble these 

 iulets of Antigua. Leaving aside for a moment the question of 

 whether the line of the Antilles is a submerged region, there are 

 several considerations adverse to the conclusion that these inlets 

 are due to denudation. The north-eastern coast of the island is 

 full of inlets and creeks with numerous islets, shoals, and banks 

 of all sizes. But there are no rivers in this region, which is that of 

 the Calcareous .Formation. It is probable that the numerous irre- 

 gularities of this coast are produced by the solution of the rocks, 

 the waters both meteoric and marine attacking and dissolving the 

 more soluble and less coherent beds, thus eating away the land 

 in an irregular and uneven contour. Simple marine erosion has 

 usually a tendency, except where the rocks are of unequal con- 

 sistency, to reduce the shore to a straight line. Pluvial erosion, 

 other than that due to solution of calcareous matter, is absent from 

 this region. 



We now take the case of the large inlets (see fig. 1, p. 683) known 

 as Falmouth, English Harbour, and Eive-Islands Harbour, which 

 are in the Igneous Formation. They are large excavations, quite 

 different in shape from subaerial valleys. There is absolutely no 

 room in Antigua, even were the rainfall increased tenfold, for the 

 rivers that would be required to excavate such valleys. The raising 

 of the land 600 feet higher, that is to the 100-fathom line, would 

 greatly enlarge the island, so that it would form one with Barbuda. 

 But this would not affect the question : for the rivers, even if any 

 could exist upon such land, the greater part of which would be 

 porous calcareous formations, would from their position have no 

 effect upon the supposed sunken valleys. The conclusion is irre- 

 sistible: these inlets are the remnants of volcanic craters, 

 and the immense quantities of matter ejected from these craters can 

 be seen all around in layers and beds on the adjacent hills. 1 



The remaining large inlets, namely the Harbour of St. John and 

 Willoughby Bay, are situated one at each end of the Central Plain, 

 and here their origin is plain enough : they are simply portions of the 

 fissure along the line of the great Antillean Dislocation. They are 



1 In papers written some years ago (1902 and previously) I mentioned that 

 the harbours of Kingston (St. Vinceut), Castries (St. Lucia), and St. George 

 (Grenada) were volcanic craters. 



