96 Transactions. 



quantity of sediment. This idea is further supported by the actual position 

 of some of the limestone outcrops, which may be far inland, and are even in 

 some cases situated within the recesses of the mountain-ranges. The sedi- 

 ment that does occur in the limestones is either extremely fine quartz sand 

 or small fragments of volcanic rock produced by volcanic eruptions of a 

 submarine nature. There is thus strong evidence that at the time or times 

 at which these limestones were formed the land was reduced to comparatively 

 small dimensions. 



It is very noticeable that in the microscopic examination of these lime- 

 stones no remains of any kind of coral has been found. This is the more 

 remarkable when it is stated that in the greensands which often occur above 

 and below the limestones there are frequently a large number of species of 

 Flabellmn and related species of coral. It is thus evident that the statements 

 which have frequently been made that the Tertiary limestones are wholly 

 or in part the remains of former coral reefs are quite incorrect, so far at least 

 as those localities are concerned from which the specimens described here 

 were obtained. This is the more important when it is realized that the 

 limestones from which these specimens have been described were collected 

 in all parts of the country, and that they include the outcrops which have 

 been referred to by other geologists as of coral origin. 



The actual depth of water in which the deposit of these limestones took 

 place is also indicated by the organic remains that occur in the rocks. 



Those limestones that consist of Polyzoa and echinoid fragments and 

 of the larger types of Foraminifera with cccasi(jnal Lithothamnimn were 

 deposited in water of no great depth. The soundings round the New 

 Zealand coast show the presence of so-called coral and coral sand at 

 depths of 105-772 fathoms to the west of Cape Maria van Diemen, in 

 places as much as 100 miles from the coast -line. Similar material 

 occurs at a distance of twenty-five miles east of the Bay of Islands 

 in water 305 and 325 fathoms deep. The only other locality in which 

 there is a record of a similar bottom is near the Snares, in water 

 77-81 fathoms deep. It is probable that this material closely resembles 

 the deposit that developed into the polyzoal type of limestones, such as 

 Whangarei, Cabbage Bay, Wiwiku Island, Tata Islands, Mount Somers, 

 Oamaru, and Winton. The echinoid remains are certainly more abundant 

 in the rock than they are likely to be in the "coral sand,"" but this may 

 indicate warmer climatic conditions. Thus in the Funafuti report (Roy. 

 Soc. Lon. Eep. of Coral Reef Com.), 1904, p. 329, it is stated, " Detached 

 spines of echinids are in many cores so abundant as appreciably to con- 

 tribute to the mass of the rock." In those locaUties where "coral sand" 

 has been found on the sea-floor in the New Zealand area the land is of 

 small dimensions, there are no rivers near at hand to supply sediment, and 

 the ocean-currents flow with greater swiftness than at other places on the 

 coast-Une. Here, then, we appear to have important evidence in favour 

 of the idea that the land was of much smaller size at the time when this 

 limestone material was deposited. 



In those instances where the limestone contains much Lithothamnimn, 

 as at Mokau and the Kaipara, it is probable that the depth of water was 

 much less, though it is noticeable that at Funafuti this alga grows at a 

 depth of 200 fathoms. The glauconite, which occurs not uncommonly in 

 the limestone, especially in the polyzoan types, also indicates clear oceanic 

 water ; but it also suggests a relatively steep coast-line and pecuUar condi- 

 tions of ocean-currents. 



