Correspondence — Meszrs. F. W. Hufton and IT. Lappingfon. 381 



feel none of those difficulties which now occur to his mind, nor 

 would he bring forward a fossil like Dictyonema, which has so exten- 

 sive a range, to prove or disprove the correlation of certain beds. I 

 look rather to the general order of the deposits, and the general 

 character of the fauna, for a clue, than to one doubtful fossil, and it 

 is on this ground that I still maintain that the Eussian faunas are, as 

 far as we can yet make out, Silurian in type, and not Cambrian. 



As to the depression in the British area being dependent upon the 

 volcanic action, I must remind Prof. Linnarsson again that we have 

 no evidence of volcanic action having taken place until the Arenig 

 period, or until after the area had been depressed to a depth suffi- 

 cient to allow from 15,000 to 20,000 feet of undisturbed sediments to 

 have been heaped up. Here his argument fails from mistaking the 

 cause for the result. For volcanic action in this case was undoubtedly 

 the result of the depression, and not the cause of it. 



Henry Hicks. 



AGE OF THE OTOTAEA FOEMATION. 



Sir, — In the note by Dr. Hector, attached to Mr. H. Woodward's 

 paper " On a Crab from the New Zealand Tertiary," I find the 

 following : " From the comparison which this table affords with the 

 recent fauna of the same area, the Ototara formation would seem to 

 have no claim to a place among Eocene formations. This is con- 

 firmed by the occurrence of a few fossils of decidedly Cretaceous 

 type, such as Saurian forms and fragments of the shell of Inocera- 

 mus, and the presence of many forms that are associated with 

 decided Mesozoic fossils in the underlying strata," ^ In the table of 

 formations given he makes the Saurians range up into the Ototara 

 series, and in the section accompanying the note he also shows : 

 " (k) Sandstones with Saurian bones, Ammonites, etc.," near 

 Brighton. 



The members present at the meeting seem also to have under- 

 stood that Secondary fossils occurred in the Ototara formation ; for 

 in the discussion Mr. Charlesworth asked " whether the presence of 

 the few Cretaceous fossils found in the deposit ivhich had furnished 

 the New-Zealand Crab," etc. 



Now I wish to point out that no Cretaceous fossils have as yet 

 been found in the rocks containing Marpactocarcinus tumidus and 

 Falceeudyptes antarcticus ; and I am not aware that any Cretaceous 

 fossils or Saurian remains have ever been foimd on the west coast of 

 the South Island. I have collected the fossils of the Ototara forma- 

 tion largely at Oamaru without finding ^any showing a Cretaceous 

 facies. F. W. Hutton. 



DuNEDiN, 3fat/ 5th, 1876. 



''ESMERILO PRETO." 

 Sir, — Can you, or any of your readers, kindly inform me what 

 was the origin of the pebbles " Esmerilo Preto ? " 



Padiham, Preston, Lancashire, H. LappinGTON. 



Mai/ 17, 1876. 



^ Quart. Joui-n. Geol. Soc, 1876, vol. xxxii. p. 56. 



