34:8 Transactions. 



the cutting was made, describes the beds, from below upwards, as bright- 

 green argillaceous sands, calcareous green sandstone with shark's teeth, 

 dark-grey micaceous sandy clay, and dark greensands. The dark-grey 

 sandy clay passes in places into hard pale-lilac flinty mudstones similar to 

 those observed in the Weka Creek. 



East Side of Weka Pass. — In the valley entering the Weka Pass Stream 

 from the east a little above the viaduct the hard bands of the' Waipara 

 greensands form a well-marked cuesta in the upper half of the valley, which 

 continues over the saddle down to the upper part of Chasm Creek. The 

 hard bands appear to be about 100 ft. above the pre-Notocene rocks, and 

 about 300 ft. below the Amuri limestone and Weka Pass stone contact. 



Chasm Creek and Omihi Valley. — In the lower part of Chasm Creek 

 and the more easterly tributaries of the Omihi Valley the Waipara greensands 

 are not exposed, owing to an overlap first of the Amuri limestone and 

 underlying sands, and finally of the Weka Pass stone on to the pre-Notocene. 



Waikare Valley. — About eight miles east of Waikare, Notocene rocks 

 appear on the south .side of the Waikare Valley and extend for some miles 

 to the eastward. A continuous section of the beds below the Weka Pass 

 stone is not exposed, but I observed in a small road entering the hills 

 near what was Mr. Davy's farm that hard banded greensandstones, exactly 

 similar to the lower group of the Waipara greensands, here form the base of 

 the sequence, and rest directly on the pre-Notocene rocks. Higher up some 

 loose sands were observed, but no typical Amuri limestone was seen, and 

 the total thickness of the beds below the Weka Pass stone does not appear 

 to exceed 100 ft. 



Kaitangatan. 



Amuri Limestone. 

 ■ The upper part of the Amuri limestone throughout the district is a 

 glistening-white, hard, very fine-grained limestone, which is generally at 

 the surface closely jointed into small cuboidal blocks. The lower part is 

 more argillaceous and greyer in colour, and has a much 'coarser fracture. 

 It passes down by imperceptible stages into a grey mudstone, and this in 

 turn becomes a glauconitic mudstone with nests of glauconite distributed 

 in an apparently capricious manner. This latter rock in the Waipara River 

 rests with apparent conformity on the Waipara greensands, and much 

 resembles the uppermost saurian mudstone immediately underlying the 

 concretionary greensands. In the eastern end of the district, however, 

 the glauconitic mudstones under the Amuri limestone rest on loose sands, 

 which appear to be interposed between them and the Waipara greensands. 

 For this reason, and because no distinctively Piripauan fossils have been 

 found in them, they have been included with the Amuri limestone. 



The microscopical characters of the Amuri limestone of Weka Pass 

 have been briefly described by Marshall (1916a), who describes it as a 

 pure Glohigerina oo^e : " The chambers of Globigerina, which are generally 

 isolated, are fairly numerous. By far the greater part of the rock consists 

 of very finely grained calcite." Near the contact of the Weka Pass green- 

 sand it " contains a considerable number of grains of quartz sand and some 

 glauconite, as well as some brown mica." 



A number of analyses of Amuri limestone from the Weka Pass have 

 been published with a view to the comparison of its composition with that 

 of pebbles in the Weka Pass greensand, or with that of the Weka Pass stone. 

 These are collected in the following table, along with analyses of the latter 

 rocks, and have been in part recalculated. 



