Bibliographical Notices. * 69 



ashes, seams of bitumen and springs of petroleum (Barbados tar). 

 The coralline limestone occupies six-sevenths of the whole area of 

 the island, and the author considers that the terraces it presents are 

 owing to gradual elevation with intervening periods of rest and sub- 

 sequent denudation, and gives a detailed account of the present con- 

 dition and probable progress of the changes it has undergone. Casts 

 of the shells of Turbo, Lucina and Petricola occur at the highest 

 elevations of the coral rock ; the shells found eight hundred or a 

 thousand feet lower still retain their lustre, but though resembling 

 those of the adjacent seas, are usually much larger than the recent. 



The "Scotland" formation presents a very different appearance 

 and structure from the coral ; the district in which it occurs is en- 

 circled by a semicircular range of heights from which long ridges of 

 hills project, converging towards each other and diminishing in height 

 as they approach the sea. The various modifications of tertiary rocks 

 of this district manifest an original uniformity, but present great signs 

 of disturbance, and the stratification varies from horizontal to ver- 

 tical, or is wavy or even contorted ; thus it is often difficult to ascer- 

 tain the dip ; the direction is generally south-west and north-east. 



The earthy marl constitutes by far the greater part of this series, 

 and it sometimes occurs stratified. It abounds in Polycystina : in 

 the marl from Mount Hillaby Ehrenberg found 54 species, belonging 

 to 22 genera ; another specimen gave 113 species of Polycystina with 

 5 of Polygastrica, 1- Geolithia and 2 Phytolitharia. 'lb the south 

 the marl is succeeded by sandstones. The bituminous sandstones are 

 intermixed with the more calcareous varieties. As to the age of these 

 rocks, our author says, " the Scalaria which I found on the summit of 

 Bissex Hill and the Nucula of Springfield, induced Prof. E. Forbes to 

 consider the Scotland rocks as belonging to the miocene period of the 

 tertiary strata. The mineralogical character of rocks is considered 

 at present of little importance when conclusions respecting their age 

 are to be formed. Still my observations on the spot, combined with 

 the mineralogical character of the rocks, lead me to coincide in 

 Prof. Forbes's opinion. The chalks of Caltanisetta, on which Prof. 

 Ehrenberg rests his opinion that the Scotland formation in Barbados 

 belongs to an older period than the miocene group, have been con- 

 sidered by different geologists as belonging to different periods ; by 

 some they have been regarded as secondary, by others as tertiary 

 rocks." 



The whole Scotland district is apparently an old sea-bottom, and 

 the author attributes its present disturbed condition to volcanic 

 agency acting from given points and thus giving rise to local de- 

 rangements. The presence of pumice and strata of volcanic ashes 

 render this less doubtful. Isolated rocks of the coral formation are 

 found lying on the summits and declivities of hills in the Scotland 

 disti'ict ; these Sir Robert i"^ inclined to regard as fragments detached 

 from the cliffs which now border the district (and which, with the 

 exception of Mount Hillaby, all exceed in height the "Scotland" 

 hills), before the upheaval of the sea-bottom. 



A description of the fossils follows this chapter, containing an 



