362 Transactions. 



main mass of the limestone, 25 ft. thick, containing at the top a shelly band 

 with Pecten huttoni, P. beethami, P. hurnetti, and Lima colorata. The 

 limestone also contains many brachiopods, including species of Rhizothyris 

 and Pachymagas, Magadina hrowni, and Terebratulina suessi. It is followed 

 by 6 ft. of sands, and a further 16 ft. of nodular limestone, which con- 

 tains Bouchardia minima, Magadina hrowni, a.nd Pachymagas sp. This is 

 followed by 3 ft. of creamy calcareous sandstone, which, as will be seen 

 later, is best regarded as forming the base of the next horizon. 



Fossils are abundant in places on the dip-slopes of the main band (D), 

 especially near the top of the small valley entering the Weka Pass Stream 

 between the 43 m. 21 ch. and 43 m. 3ch. cuttings, and over the saddle 

 at the head of this valley down to the first valley trending to the Omihi 

 Creek. Here the uppermost rubbly band seen in the railway-cutting is 

 well exposed near the foot of the main dip-slope, and yields a rich brachio- 

 pod fauna, besides Pecten hurnetti, P. heethami, Pecten sp. nov., Li^na 

 colorata, L. 'paucisulcata, L. lima, Ostrea angasi, 0. gudexi Suter (?), Anomia 

 huttoni, A. furcata, Isurus desori (Ag.), I. hastalis (Ag.), small echinoids and 

 fragments of larger species, and numerous cup-shaped and bottle-shaped 

 Polyzoa. The brachiopods identified are Terehratulina suessi, Bouchardia 

 minima, Magadina hrowni, Rhizothyris scutum n. sp., R. rhizoida, R. elongata 

 n. sp., R. curta n. sp., R. crassa n. sp., R. elliptica n. sp., R. fortis n. sp., 

 R. ohesa n. sp., R. joirum n. sp., R. ovata n. sp., R. amygdala n. sp., Pachy- 

 magas hartrumi n. sp., P. speighti n. sp., P. haasti n. sp., P. hectori n. sp., 

 P. parki, P. McKayi n. sp., P. morgani n. sp., and P. coxi n. sp. 



The uppermost Mount Brown limestone (E) forms a prominent cuesta 

 behind the dip-slope of the main band, and thence crosses the railway in 

 the cutting 43 miles 2-3 chains from Christchurch, and descends into the 

 Weka Pass Stream and Weka Creek a few yards above their junctions. 

 The succession from the main band upwards may be followed without a 

 break in the Weka Pass Stream and the Weka Creek, while parts of the beds 

 are exposed on the escarpment of the cuesta to the east. The total thick- 

 ness is about 100 ft., the last 35 ft. being formed by the uppermost lime- 

 stone, which in the railway-cutting is a reddish-brown to yellow arenaceous 

 limestone with numerous small pockets containing small pebbles, up to 

 5 in. in diameter, of greywackes and jaspers. It contains many polyzoan 

 and echinoid fragments. 



Immediately succeeding the main limestone (D) is a creamy calcareous 

 sandstone a few feet thick, well exposed jUst above the foot of the dip-slope 

 of the main band, where it yields Stethothyris suffiata and Neothyris anceps 

 n. sp. When followed over the first saddle into the most easterly tributary 

 of the Omihi Stream it forms a sharp V down-stream, and on the far side 

 is 3 ft. thick and yields Pachymagas andrewi n. sp. It is here followed by 

 a hard band 2 ft. thick, in turn succeeded by more soft creamy limestone, 

 3 ft. thick, yielding Lima colorata and Pachymagas cottoni n. sp. This is 

 again followed by another hard band 1 ft. 6 in. thick, and the exposed 

 section here ends with soft calcareous sandstone containing Lima colorata 

 and Cucullaea alta var. B. The above limestone bands are included with 

 the uppermost limestone (E) because of the occurrence in them of Stetho- 

 thyris suffiata. 



In the gorge of the Weka Pass Stream the above calcareous sands are 

 succeeded by blue muddy sands, about 50 ft. thick, which contain fossils 

 sparingly throughout, and include two shell-beds. The lower 20 ft. contains 

 Cucullaea alta var. B. and Lima colorata fairly commonly, and also yielded 



