i 7 6 



BuwmN 35 



324 



To prevent misapprehension I should note that the term 

 "deep-water" is a relative one and that while the Ditrupabed 

 maj^ be said to be "deep-water" as compared with the Springvale 

 Shellbed it was laid down in much shallower water than the 

 Naparima oceanic beds. The Foraminifer Planorbulina larvata 

 is characteristic of a depth from 15 to 200 fathoms, while JVodo- 

 saria abysorum has only been found in the recent state at 1,825 

 fathoms. 



I should notice here that the characteristic Foraminifera of 

 the Ditrupabed are absent so far as I have examined from the 

 exposure discovered by Mr. Raspass. Instead there is an extra- 

 ordinary Abundance of Planorbulina larvata a species only sparse- 

 ly represented in the shore exposure at Pointapier, but much 

 more plentiful in a sample given me by Mr. Cunningham Craig 

 from Tamana Road. I have nevertheless considered the deposit 

 discovered by Mr. Raspass to be of the Horizon of the Ditrupa- 

 bed on account of its position, mineral composition and molluskan 

 Fossils. 



My friend Alfredo Silvestri, Professor R. Liceo of Spoleto in 

 Italy, one of the greatest authorities on Foraminifera and es- 

 pecially on Orbitoides, considers those from the Manjak mine to 

 be Lepidocyclina townoueri Lem. and Douv. a varity of L. mar- 

 ginata Mich, found in Italian Tertiaries. He also finds among 

 these Orbitoides a (probably) new species of Lepidocyclina, the 



Page 33 



embryonic part of which is very remarkable. He considers the 

 Orbitoides from Antigua to be Lepidocyclina elefantina Munier 

 Chalmas, a form also found in Italian and Indian Tertiaries 

 (Aquitanian). I am unable as I have so often stated to admit 

 the validity of the distinctions so much relied on by experts to 

 characterize so-called Genera and species. While I have no 

 doubt as to the correctness of Silvestri' s identifications for my 

 own use I prefer the designations already arrived at as referred 

 to in my note on the Manjak mine. In estimating the probable 

 age of the Naparima Tertiaries we must give due weight to the 



