IN THE LOWER TERTTAEY STRATA OF NEW ZEALAND. 255 



are apparently deep-sea and shaliow-water sponges, may perliaps 

 be explained by the fact .that many genera have an extra- 

 ordinary range of depth — thus Hyalonema ranges from 95 to 

 2900 fitlioms, Esperiopsis from 30 to 1600 fathoms, Clado- 

 rhiza from 106 to 3000 fathoms ; and it is highly probable that 

 many Monactinellid genera now considered as only existing in 

 shallow and moderately deep w^ater will be found by further in- 

 vestigation to be equally capable of living in the ^ame extreme 

 depths as the more specially aby.-^sal Hexactinellids. This finds 

 confirmation in the ' Egeria ' dredgings referred to already, which, 

 thougb from depths of 2479 and 3000 fathoms, are filled with 

 detached acerate, acuate, tibiella, and cylindrical spicules of Mon- 

 actinellid sponges and flesh-spicules of such genera as Esperella, 

 Acarnus, Spirasirella, and Latriinculia ; some species of which 

 now live at depths of 10-50 fathoms. This occurrence of sup- 

 posed shallow-water sponges with deep-sea forms has alreadv 

 been commented on by Mr. H. J. Carter, who found in deep-sea 

 dredgings off the Seychelle Islands associited with Euplectella 

 the same forms of detached Munactinellid and other spicules 

 which were present in dredgings from the Gulf of Mauaar, 

 between Ceylon and the southern extren)ity of India, at depths 

 of 65 fathoms and under (Ann. & Mag. Xat. Hist. s. 5, vol. v. 

 1880, p. 439). It can hardly be alleged that the Monactinellid spi- 

 cules in this and the other cases mtntioned have been transported 

 by curieuts from shallower areas, for wa should I hen find 

 sedimentary matter mingled with them as well. 



Taking into account the close similarity in character of the 

 Oamaru deposit wnth that of the recent diatom ooze in the 

 Soutlieru Ocean, the occurrence in it of the remains of deep-sea 

 sponges, and the fact that similar detached spicules are now 

 abundantly present in deposits from depths of 3000 fathoms off 

 the S.W. of Australia, it may be assumed that these siliceous 

 beds of Oamaru were formed at depths of not less than 1000-1500 

 fathoms, which is nearly the average depth of the similar deposits 

 iu the Southern Ocean, as ascertained by the ' Challenger ' 

 Expedition. 



In conclusion w^e desire to express our obligations to Mr. H. 

 Morland, Mr. B. "W. Priest, Mr. Joseph Clark of Street, who 

 have su])plied us with many w'ell-prepared microscopic slides of 

 the material, and more particularly to Captain F. W. Hutton, from 

 whom we received the first consignment of the Oamaru rock. 



