262 FORAMINIFERAL ROCKS ON WEST COAST OF SAXTO, 



Notes Oil Certain Islands in the New Hebrides,"* but no 

 information is there given regarding the oldest limestones of the 

 group. 



On the west coast of the island of Santo, the oldest Tertiary 

 limestones are found dipping at a steep angle, and are overlain 

 with beds of tuff, soapstone and volcanic rocks. This older series, 

 Prof. David informs me, is apparently divisible into two groups, 

 marked by a slight unconformity. It is to the lower part of this 

 series (group No 7 of Prof. David's list) that I have confined my 

 observations, only dealing with such specimens as were found in 

 situ, or which by their organic contents showed them to be of a 

 similar age. 



ii. Description of the Rock Specimens. 



The localities referred to below are taken from the list accom- 

 panying the specimens, and printed between quotation marks. 



For the main part I have relied on specimen No. 182 for the 

 exact determination of species; and have at the same time made 

 full use of the thin slices of the limestones prepared under Prof. 

 David's direction, as well as several additional microscope slides 

 and sections of selected foraminifera prepared by myself. 



133. — "A pebble on small rise in the valley between Lobweri 

 and Partua Tabua, Santo. Probably in situ." A cut surface ©f 

 the hand specimen is of a purplish or dull plum colour. This 

 rock may be termed a Lepidocyclina Limestone. Its structure 

 is somewhat brecciated, and it is largely composed of tests of 

 Foraminifera (Lepidocyclina) and branchlets of the calcareous 

 alga, Lithothamnion. The interstitial structure of the rock, as 

 seen in thin sections, is partly crystalline and partly organic, 

 formed by the cementation of comminuted shell-fragments by 

 calcite; some crystals of augite and fragments of a basic lava also 

 occur in parts of the slide. Amongst the coarser organic contents 

 of the rock, plates and spines of echinoids were seen. 



• Quart. Journ, Geol. Soc, Vol. xlix., 1893, pp.230, 231. 



