THOiiaoN.— OV'y/oy// of Middle Clarence and lire Vfdleys. 339 



of greywacke, and there is a good deal of mudstone in the bottom of the 

 conglomerate. 



McKay does not describe the " grey marls " in the Dee River, but 

 his section represents the junction with the overlying conglomerate as 

 unconformable, the erosion surface on the " grey marls " being gently 

 undulating. 



Upper Sivale and Ure Rivers. — McKay describes the '" grey marls "' on 

 the western side of the Chalk Range as blue or greenish-grey unfossiliferous 

 marly beds, about 300 ft. thick, resting conformably on the Weka Pass 

 stone. They are repeated by folding or faulting farther to the westward. 



Farther to the north-east the " grey marls " apparently disappear 

 through the pitching of the inverted syncline to the south-west, Amuri 

 limestone being continuous across the Ure River from Brian Boru and 

 Isolated Hill to the White Bluii's. In the middle Ure, below the gorge, I 

 have already described the beds which underlie the Amuri limestone, but 

 which, owing to the probable inversion of the strata, may represent the 

 Weka Pass stone and " grey marls." 



Dart River. — McKay describes the " grey marls " as about 500 ft. thick 

 and resting conformably on the limestone. Fossils occur as nests in and 

 sparingly distributed through the grey or greenish marly clays, including 

 Galeodea senex Hutt., Ancilla sp., and Pecten aff. zitteli Hutt. Fine-grained 

 concretions similar to those in the Mead Gorge are found, but do not 

 yield fossils. 



Muzzle River. — Here again the " grey marls," according to McKay, 

 are about 500 ft. thick. Resting on the Amuri limestone is a band of 

 tufaceous calcareous greensand with Waldheimia sp. and Cristellaria haasti. 

 Higher beds consist of dark-grey or greenish sandy clay, parted by thin 

 beds of calcareous sandstone, some of which are richly fossiliferous and 

 yielded Cristellaria haasti, Pecten zitteli, Venus ? sp., a small, stronglv-ribbed 

 Pecten, small univalves, Rhi/nchonella sp., and Echinoid fragments. 



Bluff River. — McKay does not describe the nature or thickness of the 

 " grey marls " in this section, but mentions the occurrence of Pecten 

 zitteli and Galeodea senex, with casts of Malletia, Leda, corals, &c. 



Herring River. — McKay does not describe the " grey marls " in this 

 area, but his section shows their presence between the Weka Pass stone 

 and the great Marlborough conglomerate, and they are enumerated as 

 " grey marls containing Dentalium, Natica, Foraminifera." In describing 

 the conglomerate, he mentions that at the top of a high cliff on the left of 

 the junction of the Herring River with the Clarence River the Weka P^ss 

 stone is in contact with the older rocks (pre-Notocene) along the fault-line, 

 and this I also observed. At lower levels McKay describes an agglomerate 

 resting on the " grey marls," and consisting of blocks of Amuri limestone, 

 Weka Pass stone, saurian concretions, and blocks and concretions of middle 

 Tertiary rock without any evidence of stratification. He seemed uncertain 

 of their dip, but estimated the thickness at 200 ft., and considered them 

 involved in the fault-angle. It is difficult to see how, if the Weka Pass 

 stone, which is dipping towards the fault, rests against it at the top of 

 the cliff, younger beds can be present against the fault at lower levels. 

 McKay did not recognize the layer of mudstone, similar to the '" grey 

 marls," which separates the Weka Pass stone in this area into an upper 

 and lower band, and I believe he has taken an exposure of this rock 

 for the " grey marls " and has mistaken a talus deposit for the great 

 Marlborough conglomerate. In this case the '' grey marls " are absent in 

 this section. A closer study of the upper beds of this area is desirable. 



