8 P. T. C LEVE, 



The small flat cays near Cruz Bay are bluebeache-rocks and Cruz Bay is also built 

 upon the same kind of rock, which extends south wards to Marie Bluff, where felsitic rocks 

 cornmence. At the point east of Marie Bluff, the felsite is interrupted by a dark-coloured 

 amygdaloid trap. The felsite extends to Rams Head, and the small Duck's Island*) at the 

 opening of Coral Bay seeins also to be composed of a felsite of basaltic structure. The 

 large branch north of Coral Bay consists of different kinds of rocks, principally of felsite, 

 often with a kind of slaty cleavage and interrupted by trap-like rocks. The same slaty 

 felsite, graduating to fine-grained mica or talc-slate is visible by the Moravian Church near 

 Caroline Estate in almost vertical strata, striking east to west. On Caroline-Estate the 

 rock is härd, compact, felsitic stone, in which lighter coloured spöts indicate the original 

 stratification. The hills around Caroline Estate are, to judge from the very altered sur- 

 face, stratified slaty rocks. Near the coast south of Caroline Estate black clay-slate occurs. 

 Near Mount Pleasant occurs bluebeache; it continues to Little Maho Bay and the whole 

 way to Cruz Bay. The bluebeache conglomerate has some trace of stratification. The 

 strata are almost vertical and strike E — W. The surface of the rock is very denudatedj 

 and sometimes table-like, vertical parts of strata, often of considerable sizu, project from 

 the ground, as north of Cruz Bay. On the shore near Little Maho Bay are regular strata 

 of a black clay-slate striking E — W. and dipping to the north. Around the path-way 

 near Maho Bay are many loose fragments of a gray, crystaline limestone. The latter rock 

 is visible »in situ» near Anna Bay, where it contains some Wollastonite in long and flat 

 crystals. The limestone is enclosed between strata of various rocks, mostly clay-slate, im- 

 pure calcarious silex, hornblend or garnet rocks. These rocks form the small Whisling 

 cay and a part of Marys Point. Théy are often intersected by diabase dikes, and con- 

 tain much garnet and epidote, and smaller veins or fissures filled with desmine and cal- 

 carious spar. Some of the hornblend-rocks graduate into diorite. In the north part of 

 Marys Point is a large mäss of syenite-like diorite, which rock is also visible near Browns 

 Bay. The rock is a middling coarse granular mixture of white lime-oligoklase (Hafnefjor- 

 dite), black hornblend and black or bronze-coloured mica. Near Browns Bay the diorite- 

 inass separates into branching and anastomosing veins and dikes, that run into the sur- 

 rounding rocks. The diorite contains some epidote, brown garnet, small yellow crystals of 

 spén, and, on the fissures, desmine or quartz and feldspar. The rock also contains traces 

 of copper. Near Menuebecks Bay stratified rocks are visible among the seacliffs. They 

 strike E — W and dip 60° to the south. South of Menuebecks Bay are felsitic and trap- 

 like rocks, containing white quartz with spén and titanitic iron. 



5. Tortola is an island of about the same size as S:t Thomas and extends from 

 east to west. It is mountainous and the highest peak Mount Sage reaches 543 metres 

 above the sea. The mountains are generally very steep and the rock in the middle of the 

 island is bluebeache as in S:t Thomas. At the east-end diorite occurs, and from Buck's 

 Island to Brandwine Bay the cliffs along the shore are composed of a dark, fine-grained, 

 amphibolic and micaceous stratified rock. West of the Seacow Bay occur stratified meta- 

 morphic rocks of an occasionally garnetiferous silicious limestone. The cornmon strike of 



*) I did not go ashore on the island, but passed very near to it. 



