266 CAPT. r. "\v. Hiriio:s ox the geological position 



27. On the Geoiogical Positiox of the " Weka-pass Stoxe " of New 

 Zeala2s-d. By Captain P. W. Huttox, F.G.S. (Eead June 2b^ 



1884.) 



The northern part of Ashley County, in the Province of Canterbury, 

 is, to the geologist, one of the most interesting districts in !>Tew 

 Zealand ; for, as Dr. von Haast has truly remarked, it " offers us the 

 key to unravel the relations in which our young Secondary and old 

 Tertiary beds stand to each other." And as all the more important 

 of the I^ew-Zealand coalfields belong to one or other of these groups 

 of rocks, the district becomes highly important from an economic 

 point of view. 



The district in question is bounded on the north by the Hurinui 

 Eiver and on the south by the ^aipara Eiver, so well known to 

 geologists as the locality whence Plesiosaurus australis, Owen, was 

 obtained b}' ]\Ir. Cockburn Hood. It is crossed by the railway and 

 road from Christchurch to i^elson, which here pass over a low 

 range of hills by means of a depression called the Weka Pass, which 

 gives the name to the limestone that forms the subject of this 

 paper. In it there occurs a white, flaggy, argillaceous limestone, 

 known as the Amuri limestone, which at both the "Waipara Eiver 

 and Weka Pass lies conformably on green sandstones. All geologists 

 who have visited these localities agree that the Amuri limestones 

 and the green sandstones are parts of the same rock-system, which 

 is called the Waipara System by Dr. von Haast and myself, and 

 forms part of the Cretaceo-tertiary System of Dr. Hector and the 

 officers of the Geological Survey of jSTew Zealand. This Waipara 

 System is considered to be of Cretaceous age, because the green sand- 

 stones contain remains of marine Saurians and rest conformably 

 on beds of coal and shales, containing leaves of dicotyledonous Angio- 

 sperms, that form the base of the Waipara System. 



Above the Amuri limestone, both at the "Waipara and Weka Pass, 

 comes an arenaceous limestone, usually with small green grains 

 scattered through it, caUed the Weka-pass Stone. It is of a 

 yellowish white colour, but weathers white like the Amuri lime- 

 stone. Above the "Weka-pass Stone is a grey trandy marl, and 

 above this, again, come thick beds of pale yellowish sandstone, with 

 bands of shelly and coral limestone. These last beds, lying above 

 the grey marl, are acknowledged by all J^ew-Zealand geologists to 

 be, probably, of Upper Eocene or Ohgocene age. They are "(he 

 Mount-Brown beds of the Geological Survey, and form the upper 

 part of the Oamaru System of Dr. von Haast and myself. 



So far all are agreed ; but opinions differ as to where the line 

 separating the Waipara System from the Oamaru System should be 

 drawn. Dr. Hector and Mr. M'Kay think that it should be taken 

 between the Grey Marl and the overlying Mount-Brown beds ; Dr. 

 von Haast would make it between the Weka-pass Stone and the 



