194 DE. G. J. HINDE. 



&c., are intermingled, and fine calcareous sediment is present in the layers of both 

 kinds. Such alternation of layers or bands of corals and foramiuifera appears to prevail 

 throughout this lower third of the boring, Ijut it is better marked in some parts 

 than in others. There are indications that even in the upper parts of the boring a 

 similar alternate disposition takes place, but as a result of the slight cementation the 

 layers of foraminifera and fragmental organisms are resolved into their constituent 

 elements. Owing to the manner in which the different layers gradually merge into 

 each other, it is not practicable to determine their I'elative proportions with accuracy, 

 but it is clearly evident that the length of the foraminiferal and detrital layers in the 

 cores considerably exceeds that of the coral layers. 



The corals in this lower third of the boring are, as a rule, very badly preserved, 

 the dolomitisation having been more effectual in obliterating their characters than 

 where the matrix is of limestone ; in some instances, however, the more durable 

 character of the matrix has retained sharper and more distinct casts of the original. 

 They are proportionately more numerous and varied than in the higher parts of the 

 boring ; some are also of larger dimensions than those met with in the higher cores ; 

 thus, for example, the vertical diameter of a specimen of Poritcs arenosa from the 

 depth of 970 feet measured 13 inches (825 millims.). In many instances the corals 

 in the layers appear to be in their position of growth, their upper surfaces being often 

 closely invested with repeated encrusting layers of Polyti'cma and Lithothamnioii, 

 and on these otlier corals have in turn fixed themselves in the same way as in a 

 recent coral-reef 



Most of the genera of corals are the same as those noted in the higher part of the 

 boring, but some, e.g., Enpliyllia, IIy<hiophora, (xcdaxea, Sidei-a.str<eaa,nd Psammocora 

 — well known recent genera — have only been recognised in the cores of this lower 

 division. The genera most numerously represented are Millepora, Lobophylum, 

 Stylophora, Se riatopora, Pociilopora, Caloria, Aatroea, Prionaslrcea, OrhiceUa, 

 Cyclosens, Madrepora, Montipora, AstrcBOpora and Porites. This last genus is 

 especially abundant. All the genera belong to existing reef-building types. 



The foraminifera present in the lower part of tlie boring are the same forms which, 

 with one or two exceptions, occur in the upper part as well. The predominant genera 

 are Orhitolites, T'exiidarui, PlanorhnUiia, Carpenteria, Calcarina, GyjJsina, Polytrema, 

 Amphistegina and Heterostegina. 



Echinid spines, lamellibranchs and gastropods (as casts) are fairly common to the 

 bottom of the boring. Halimcda joints and brandling Ldhothamnion are also present ; 

 the latter is very common.'* 



The only fragment of a vertebrate met with in any part of tlie boring was a small 

 fish-bone or spine, embedded in liard dolomitic rock, at a depth of about 1062 feet. 



8cL' p. 157. 



