424 ' tr((ni>actions. — Oeulogy. 



In his earlier report, Mr. McKay says : " The outlier of these 

 rocL'S [Pareora] between the Kakaiiui River and the Upper 

 Waireka shows them to be quite unconformable to the Ototara 

 limestone and the tufas and greeusands uuderlyiug the lime- 

 stone, as the limestone is absent and the conglomerates and 

 blue clay seem there to lie on the tufas and basaltic rocks which 

 are the northern continuation of the Mount Charles rocks at 

 Otepopo. This conclusion is quite irresistible, if we consider 

 the upper part of the valley of the Waireka as due to denudation, 

 aud not to a fault, which latter it could not well be."* It will 

 be seen that my observations confirm this (except the relation 

 to the rocks of Mount Charles) ; but in his last report Mr. 

 McKay abandons his former views without any remark except 

 the statement that these beds are overlain by the Maerewhenua 

 limestone,! for which he 'adduces no evidence, and gives no 

 section nor list of fossils. Mr. McKay, however, collected 

 fossils in the Upper Waireka Valley, as well as beyond the first 

 tunnel on the Windsor-Livingstone railway, which will, I hope, 

 settle the question when they have been accurately named. 



Silt Formation. — In my report on the Geology of Otago in 

 1875, I gave a section of the silt deposit, or loess as it has been 

 called, on the north side of Oamaru Peninsula, and stated that 

 it rested upon gravels with marine shells. Quite lately Dr. 

 Hector has called this in question. He says : " As far as 1 have 

 observed, the presence of such shells under silt can always be 

 accounted for by landslips of the slope deposit."^ I therefore 

 paid particular attention to this point, and can state confidently 

 that on the north side of Oamaru Peninsula gravels with marine 

 shells undoubtedly underlie the silt conformably. The chffs 

 have here been cut back for some distance to form the railway to 

 the port ; all traces of raised beaches, if they formerly existed, 

 have been removed, and a true section has been exposed ; as is 

 proved by the intercalations of gravel and silt. But more than 

 this : at the place where the railway sidings commence at the 

 port, the cutting has exposed a large cave in the volcanic rocks 

 which has been filled up to the roof with silt. On the floor of 

 this cave are the gravel beds with marine shells, and these are 

 covered by well-stratified sandy beds, passing up gradually into 

 the silt, which is continuous with that of the rest of the clifl:", as 

 is clearly feen in the cutting. In this case a landslip is impos- 

 sible, for the beds are covered by the roof of the cave ; and if 

 the fossiliferous beds pass under the silt here they must also do 

 so in other parts of the cutting. On the south side of the 

 peninsula, slips have, no doubt, occurred in places ; but even 



• " Eep. Geol. Expl.," 1876-77, p 57. 

 t " Eep. Geol. ExpL," 1883-81, p. 59. 

 } "Rep. Geol. Expl.," 1883-84, Progress Report, p. xxv. 



