272 Transactions. 



2. Greenish glauconitic sand passing up into glauconitic limestone, the 



glauconitic material being disposed in irregular patches and 

 lenses, giving the rock a somewhat streaky appearance ; it is 

 also full of worm-borings filled with glauconitic material. This 

 passes up into 



3. Amuri limestone, 25 ft. thick, with less glauconite than 2. The passage 



beds between this and the lower bed consist of fragments of Amuri 

 limestone in a greensand matrix, the limestone finally taking on 

 the facies of the typical Amuri stone, being white and jointed into 

 quadrangular blocks. The strike is as before, but the dip is less, 

 being about 30°. 



4. Glauconitic limestone, 20 ft. thick, comparable w^ith the Weka Pass 



stone as it approaches a shore-line (Speight and Wild, 1918, p. 77), 

 but passing up into a more sandy facies. 



5. Marl, slightly sandy, with concretionary layers and rounded con- 



cretions. This is the stratigraphical equivalent of the " grey 

 marl " in the Weka Pass district. It has the same strike and dip 

 as the limestone, and its thickness is about 70 ft. 



Thus far the sequence is quite clear and conformable, but for a time the 

 exposures are obscured and the relations to the underlying beds are not plain. 



Just below the gorge there is a well-marked bed, striking north-north-east, 

 with slightly flatter dip than the limestone, and containing numerous speci- 

 mens of Ostrea ingens. Farther down-stream, but higher in the series, is a 

 sandy conglomerate followed by sands with broken shells. These pass up 

 into sands with a layer of oyster and other shell fragments, and then follow 

 the beds of the Kowai series. 



These are first exposed at the mouth of the gorge, just above the site 

 of the old sawmill. They consist of sands and sandy gravels containing 

 shell-fragments and showing intraformational unconformities, but no clear 

 evidence, given by sections, of an unconformity between the Kowai series 

 and the lower Tertiaries. Almost everywhere in the case of gravels resting 

 on sands or other finer detrital beds the upper surface of the latter has 

 suffered some erosion, but in no case in this branch of the Grey does this, 

 in my opinion, amount to sufficient to be considered a major unconformity. 



On the next bluff down-stream, and higher in the sequence, the beds 

 exposed consist of greenish-grey sands (weathering light-brown) and sandy 

 gravels, with sandy carbonaceous shales and impure lignite. These are 

 capped unconformably by terrace-gravels belonging to the early history of 

 the Grey River. This sequence is repeated on the next bluff, but the 

 gravel beds of the Kowai series become more important, one very heavy 

 band of gravel near the top of the cliff being divided into two parts by a 

 layer of carbonaceous shale. In the bed of the river, at the base of this 

 cliff, is a section which shows an unconformable junction between a greenish 

 sand and an overlying bed of gravel. After a careful consideration of the 

 circumstances of this case I have come to the conclusion that it must be 

 considered only as an intraformational unconformity, due to the erosion of 

 the bed of sand by marine currents in the interval between its deposition 

 and that of the succeeding layer of gravel. 



These beds strike north-east, and dip south-east at an angle of 20°. 



As the sections are followed down-stream their character does not change 

 except that the gravels become increasingly important, a feature that is 

 well exemplified at the Horseshoe Cliff, on the face of which gravels greatly 

 predominate, some layers being from .50 ft. to 70 ft. in thickness. Well- 

 defined sandy layers also occur. The regular stratification of the beds 



