32 P. T. CLEVE, 



of it has the appearance of amber and is half transparent; other specimens have formerly 

 been corals or limestone full of fossils; the carbonate of lime having been exchanged for 

 phosphate. 



Concerning the coinposition of the phosphate of Sombrero and of other West-Indain 

 Islands see: 



Phipson and Julien in Sill. Am. J. Se. and Arts Vol. XXXVI (1863) p. 423. 



Taylor Sill. Am. J. Se. and Arts (1857) p. 177. 



Sandberger Leonh. & Gein. Neu. Jahrb. fur Min. ( 1870) Ho. p. 308. 



DAdhemar Bull. Soc. chimique de Paris 1868 p. 315. 



See also for the formation of the phosphate Hague: On Phosphatic Guano-Islands 

 of the Pacific Ocean (Sill. Am. Journ. [11] 34. 1862) p. 224. 



Rocks from the North-eastern West-India Islands. 



1. Limestone without fossils occurs in the Virgin Islands, as in Ginger Island (light- 

 gray crystaline), Congo Cay (grayish-blue crystaline with parallelopipedic cleavage), S:t John 

 between Brown's Bay and Mary's-Point (härd gray sometimes with Wollastonite,), Tortola 

 (the west-end) and Great Thacht Island (härd, gray, crystaline and often containing nu- 

 merous garnets). , 



Compact limestone with traces of fossils and of grayish colour is found at Judith's 

 Fancy on the island of S:te Croix. Gray, compact limestone with fossils occurs in S:t 

 Bartholornew. 



White, härd and compact limestone with fossils occurs in Puerto Rico, Anguilla, Ane- 

 gada, Sombrero etc. 



Soft and chalk-like limestone is the constituent of Brimstone Hill in S:t Kitts. 



Coral-limestone occurs in S:te Croix. 



Becent coral-sand-stone occurs in most of the West-India Islands along the shores. 

 It consists of small worn pieces of shells, corals and calcarious algge bedded together to 

 compact banks. 



The surface of the limestone is often in the West-Indies very rough and contains 

 numberless small pores. 



Silicious Limestone or perhaps more correctly Silicious marl-stone is a gray or greenish, 

 härd and stratified rock, which often contains garnet or epidote. It frequently occurs in- 

 terstratified with metamorphic rocks as micaslate, amphibolitic slate, clayslate, etc, and is 

 very common in the cretaceous formation of the Virgin-Islands and also in the island of 

 S:t Martin (probably of eocene date). 



Mari. White chalk-like marl occurs in thick beds in the south-western part of S:te 

 Croix. One specimen, taken near Mary's fancy, has been analyzed by Mr C. O. Lund- 

 holm. It contains Ca C 71,33; Mg C 0,72; Si 14,96; Al 3,45; Fe 2,oo; K0,n; Na 0,06; Hand 

 loss 7,37. Sum. 100. 



2. Quartzite in the form of veins is very common in the creataceous formation of 

 the Virgin-Islands. Large masses of a kind of quartzite, probably metamorphic sandstone, 

 is found on Virgin Gorda in the middle part of the island. 



