174 PROFESSOR J. W. JUDD. 



algal growths, have not hitherto attracted the atteiitiou which they deserve. Tliere 

 is evidence that they abound in many coral-reef deposits in all parts of the world. 



The question of the existence of anything like stratification in the materials 

 building up the reef rock was one to which special direction was directed. 

 Professor David, whose notes on the specimens were of great service to us, called 

 attention to several cores, on the outside of which obscure markings suggesting 

 stratification, usually with a very steep dip, were noticed by him. These cores were 

 carefully cut at right aiic/les to the supposed dipping laminae, and in all cases the 

 appearances proved to be fallacious. The numbers of the cores in which something 

 like stratification was suspected were 61a, 67a, 89a, 125a, 178a, 194a, 321a, 327a, 

 328a. The description of these cores, by Dr. Hinde, will be found in his report, and 

 the numbers of all cores in which stratification was suspected is given, so that our 

 remarks upon them can be verified in either the British Museum or the Sydney 

 Museum halves of the cores. The conclusion at which we arrived was that nowhere 

 could a stratification, such as might be expected in a talus-formation, be found, but 

 only such irregular accumulation of detrital materials as takes place between and 

 around the corals ; and these appearances were presented at many points, from the 

 top to the bottom of the Ijore-hole, whenever consolidated rock could be examined. 



Another point on which very careful observations were made, was with a view to 

 determine if anything like an admixture of dee})er- water organisms cmild be detected 

 among those building up the reef The numerous dredgings made by Professor David, 

 with the aid of Messrs. Finckh and Halligan, enable us to understand the nature of 

 the flora and fauna of the ocean-face of the reef down to 200 fathoms, while the deep- 

 sea soundings made by Captain Field, in H.M.S, " Penguin," supply information as 

 to the organisms living at still greater depths. Now, had any portion of the rock of 

 the core consisted of material fallen from above, and resting at lower points on the 

 ocean-slope, we should expect to find an admixture of these shallow-water forms that 

 had fallen with others belonging to a greater depth which had grown on and around 

 the fallen fragments. But distinct as are many of the forms of life which occur living 

 on the ocean-face of the reef between 100 and 200 fathoms, not a trace of these was 

 found in the lower portions of the Funafuti core. Dr. Hinde's carefully drawn-u]) 

 lists show that from top to bottom the same organisms occur, sometimes plants, some- 

 times foramiuifera, and sometimes corals predominating ; but in the whole depth bored 

 the same genera and species of these various grou])s of organisms take their part in 

 the building up of the mass. 



As the rocks through a large portion of the l;ore-hole showed such striking evidence 

 of having undergone great chemical and mineralogical changes, the question of the 

 possible existence of older Tertiary limestones forming the basis on which a modern 

 reef had grown up, became one which it was evidently necessary to keep in mind. 

 The circumstance that both in the Indian and Pacific Oceans coral reefs founded on 

 old Tertiary limestones are known to exist, made investigation of this point very 

 desirable. 



