CALCAREOUS FORMATIONS OF THE SOLOMON GROUP. 555 



view is near the south side of the island. The large stream that opens into 

 the harbour close to the village of Saveki, cuts through, at a distance of some 

 300 yards in a straight line from the coast, an amygdaloidal clolerite. This 

 rock, which is here exposed in mass, is often porphyritic in structure. Up 

 the adjoining slope of the hill-spur on the right side of the stream, fragments 

 of this and other volcanic rocks may be found on the surface. At the height 

 of 300 feet it is exposed in situ ; and at intervals on the hill slopes above 

 small fragments of volcanic rocks of somewhat varying characters* may be 

 observed, even up to 900 feet above the sea. I have little doubt therefore but 

 that the mass of the spur, overlooking the village of Saveki on the west, is of 

 volcanic formation, being merely encrusted by the recent Foraminiferous muds 

 and coral rocks. 



History of the Formation of the Island. — By a reference to the section of 

 Treasury Island (PI. CXLIV. fig. 4), its structural history will be readily under- 

 stood. An ancient submerged volcanic peak, having been covered by a thick- 

 ness of several hundred feet of deposits, for the most part resembling the 

 muds now being formed around oceanic volcanic islands, has finally been 

 encrusted with coral reefs and been elevated above the sea to a height of 

 nearly 1200 feet. How far beneath the surface of the sea this volcanic peak 

 may have been originally submerged, it is difficult to say. But as bearing 

 on this question I may here quote from Mr Murray's description of a hard 

 Foraminiferal limestone, which was found at the surface. " The organisms in 

 this rock, as well as the minerals, are," he writes, " similar to those found 

 in deposits of modern seas in depths from 500 to 800 fathoms, near volcanic 

 islands." The class of hard Foraminiferal limestones has already been referred 

 to in connection with Treasury Island (p. 554). 



That there have been pauses in the elevatory movement, there can be no 

 doubt ; but only the latest have left their marks behind at the present day. 

 Thus, the broad ledge of coral rock which forms the sea-border was the work 

 of a lengthened interval, since which there has been an upheaval of from 50 to 

 100 feet. At that time (vide Plan and Section PI. CXLIV. figs. 3 and 4) Stirling 

 Island appeared at the surface as a line of barrier-reef off the weather coast of 

 Treasury Island, from which it was separated by a deep lagoon-channel between 

 50 and 60 fathoms in depth — the present harbour. The islets of coral rock, 

 that lie inside Stirling Island, may possibly mark the position of other 

 volcanic peaks. We have, however, in the coasts of the harbour and in the 

 cliffs of Stirling Island, evidence preserved of yet more recent pauses in the 

 elevation. An old sea-level is indicated in several places, since which there 

 has been an upheaval of some 10 or 12 feet. But the most modern upheaval 

 is shown in the margin of recently elevated and often well-preserved corals, 



* Augite-andesite and porphyritic felsite, &c. 



