g8 THE BUILDING OF AN ISLAND. 



fineness, Radiolarian ooze. The Radiolaria are near cousins of the Foraminif- 

 era, but their coverings are not made from lime, like those of the latter, but 

 from the clearest silex; and when they are seen through the microscope, this 

 quality, along with their greatly varied and beautiful forms, make them very 

 attractive objects. The Radiolarian shells of the present day are found in 

 water 10,000 feet or more in depth ; hence it has been argued that the Scotland 

 beds, which belonged to shallow seas, must have sunk to at least that depth. 

 How long did they remain there to take the considerable thickness of those 

 fine-orained beds on their surface? It is impossible to answer, but when we 

 think of the fine rain of these microscopic skeletons descending on the ocean 

 floor, we must conclude that an immense time must have elapsed before it 

 could have produced such a thickness of strata as the later elevation has made 

 visible. The Scotland beds contain a substance which Sir Robert Schomburgh 

 describes as coal. Mr. Jukes-Browne speaks only of the " black bituminous 

 clays " of the Scotland formation. Locally the product is known as vianjack. 

 Petroleum is obtained from the same formation. The presence of such beds, 

 however they may be described, is sufficient to prove the existence of an 

 abundant vegetation in that ancient land, just as the agatized woods prove it 

 for Antigua. 



Dr. Spencer says that the age of the Scotland beds has not been settled, 

 but he thinks from their very great total thickness that they must be dated 

 probably as far back as the Eocene time. It is worth noting that these beds 

 were very much disturbed before they went down into the sea, for they dip in 

 various ways at different places, yet were planed down before sinking, so that 

 the " oceanic beds" rest upon their upturned edges, or, in geological language, 

 they rest unconformably upon them. The uppermost bed of the oceanic series 

 is a twenty-five feet of thickness of " grey volcanic mudstones," which the 

 authors consider to have been probably formed from volcanic dust drifted from 

 distant volcanoes, as there is no sign of any volcanic outburst on Barbadoes. 

 It is interesting to note that radiolarian earth is also found in Trinidad, Cuba, 

 Hayti and Jamaica. 



From the above facts and expert opinions it seems likely that there was 

 an old north and south axis long before the present volcanoes existed, and pos- 

 sibly as old as our east and west axis. 



While the settlement of questions of age must be left, as already said, to 

 the pakeontologists, the geological facts available are very instructive, for we 

 see that these other islands have, like our own, accumulated the materials of 

 their construction from different sources, and have been subjected to elevations 

 and depressions similar to those which we have seen to have taken place in our 

 own island. 



