78 Geology of Antigua. 



character of a conglomerate, but are much less inclined, and 

 have been less subjected to heat. 



The remaining formation is the calcareous. It is far the most 

 extensive of the three, and comprises the north and northeast 

 parts of the island. It is no where very elevated — the highest 

 hills not rising more than 300 or 400 feet above the level of the 

 ocean. The surface of the ground is generally undulating ; 

 sometimes the hills are abrupt and broken, having summits cov- 

 ered with a light soil and overgrown with tropical shrubs, partic- 

 ularly Lantana involucrata, Pisonia subcordata, and Croton bal- 

 samiferum. The slopes of the hills and the lower grounds are 

 highly cultivated ; and, in an agricultural point of view, consti- 

 tute the best portion of the island. This formation is separated 

 from the preceding by a low tract, extending from Dickinson's 

 Bay to Willoughby Bay, which Dr. Nicholson thinks was, at no 

 very remote period, submerged, and divided the island into two 

 nearly equal parts. 



The composition of this formation, like that of the correspond- 

 ing one in St. Croix, is by no means uniform. In many places, 

 it consists of marl, which may be easily quarried with a heavy 

 hoe ; in others, it is a tolerably compact limestone which can be 

 broken only with a hammer. I did not observe any specimens 

 of what I called " coral crag" in the geology of St. Croix, though 

 further observation might have brought them to light. Dr. Nu- 

 gent describes strata running through the marl, which I had not 

 an opportunity to see, " consisting of a grit stone, divisible into 

 thin layers," and appearing under a magnifying glass to be "made 

 up of very minute fragments of quartz, hornblende, jasper, horn- 

 stone, and green earth, held together by an argillaceous cement." 

 It also contains localities of a yellow calcareous sandstone, break- 

 ing with an earthy, conchoidal fracture, and employed extensively 

 in architecture. As a group, this formation is_ stratified ; but, in 

 many places, the planes disappear, and the mass bears the aspect 

 of a precipitate from water. Though it obviously rests upon the 

 clay, the strata of the two formations are not conformable ; those 

 of the marl being sometimes horizontal, and at others inclined in 

 different directions. 



This formation contains a great variety of fossils. " Of these 

 we may enumerate," says Dr. Nugent, " as most frequently pre- 

 senting themselves, different species of madrepore, echinus, ser- 



