410 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



[May 6, 



in the same state of preservation as the Shells sent over by Dr. Nugent. 

 Those which I have examined are principally gigantic Astraeans, 

 covered with casts of their calices, and presenting every variety of 

 fossilization, from perfect universal silicification to imperfect silicifi- 

 cation of the original hard tissues and filling up of the interstices with 

 granular carbonate of lime. Theyare less perfectlysilicined than in the 

 other strata, are usually of a yellow-ochre colour externally, and are 

 remarkable for their luxuriant growth. Some terrestrial Shells are 

 found in the Marl, and the Corals, generally, are more or less affected 

 by the matrix in which they were imbedded. The Inclined Strata 

 appear to have been Coral-formations of no very great luxuriance ; 

 and their partial and irregular upheaval by the trap was previous to 

 the formation of the unconformable Chert, which is in the exact posi- 

 tion of a fringing reef. The Chert, as far as can be determined from the 

 Corals, was formed under external circumstances not very different 

 from those under which the Inclined Beds were deposited; both 

 contain fossil Woods in great quantity. The Marl, formed as a reef 

 around the Inclined Beds during times of considerable variation of 

 level, quite surrounds the Chert, and is found above, below, and out- 

 side it. Fragments of the Chert are found in the Marl, which has 

 also suffered greatly from denudation. There is no Wood in the 

 latter formation, and the Corals are luxuriant and gigantic. Here 

 there are evidences of a change in the external circumstances which 

 affect coral-growth — probably the absence of the current which 

 carried down the trees whose fragments, often many feet long, are 

 found mixed with the Corals of the older beds. 



The Corals of the Marl are closely allied to some of those in the 

 older beds. Here are three consecutive coral -formations, furnish- 

 ing the support for the growth of existing reefs, and evidently 

 developed according to the same processes now in action in the sur- 

 rounding sea. 



B. Enumeration of the Species. 

 I. From Antigua. 



a. From the Marl. 



la. Astrcea crassolamellata, sp. noy. 



lb 



1c. 



Id. 



le. 



If. 



V- 

 3. - 



4. - 



-, var. magnet ica. 

 -, var. pulchella. 

 -, var. nobilis. 

 -, var. minor. 

 -, var. Nugenti. 

 -, var. magnifica. 



2,3. 



Antiguensis, sp. nov. 

 endothecata, sp. nov.t, varr. 1, 



6. Astra? a tenuis, sp. nov. 



7. Barbadensis**, sp. nov. 



8. radiata, Lamarck, var. inter- 

 media. 



costata, sp. nov. 



9.- 

 20. Ehodara?a irregularis, sp. nov. 

 21a. Alveopora Dredalaca, Blainville, 

 var. reffularis*. 



22 

 2& 



microscopica, sp. nov. 

 fenestrata, Danai. 



* Common to the Chert and the Marl, 

 f Common to St. Domingo and Antigua. 

 ** Common to Barbadoes and Antigua. 



