Gudex. — Succession of Tertiary Beds in Pareora District. 251 



addition some fish-remains, echinoderm-spines. and the following corals : 

 Flabellum sphenodeum T.-W., Balanophyllia hectoii T.-W., and Spite not melius 

 huttonianus T.-W. 



The chalky limestone has no fossils excepl Foraminifera and other micro- 

 scopic forms, while the dark limestone and the ordinary limestone have 

 only a few brachiopods — viz., Pachymagas ellipticus Thomson and Aetkeia 

 gualteri (Morris). 



Bluecliffs. 



Following the Otaio for four miles, we come to a long line of cliffs of blue 

 clay, whence the district takes its name. These beds can be traced all 

 the way from the Otaio Gorge, and are certainly resting on the limestone, 

 though no actual junction is shown. The relation of the two beds, how- 

 ever, is clearly seen at Squire's, Gordon's Valley, Cannington, and Mount 

 Horrible. 



W.N.W. i st 5£S£ 



Fig. 4. — Section along Otaio River at Bluecliffs. Distance, about § mile ; 

 direction, W.N.W.-E.S.E. ; dip, 20°. 1. Blue clays. 2. Lower part 

 of the red sands, with concretions. 3. Middle part of the red sands, with 

 calcareous sandstone. 4. Upper part of the red sands. 5. Gravels. 



The blue clays seem to reach their maximum thickness here, for they 

 are at least 350 ft. thick (see fig. 4). The fossils occur very sparingly, 

 but the great exposure of strata enables one to make a good collection. 

 These bluish-green clays yield the molluscs tabulated in column 5 of the 

 table of fossil mollusca, and in addition small nautiloids, annelids, scutes, 

 and Pachymagas parki (Hutt.), Trochocyathus mantelli T.-W., Flabellum 

 circulate T.-W., and F. laticostatum T.-W. 



Southburn Cutting. 



At the Southburn Cutting, at the end of the Bluecliff section, the blue 

 clays are seen passing into red sands, with concretions. Higher up in 

 these sands there are bands of calcareous sandstone. These beds are not 

 richly fossiliferous, like the corresponding beds elsewhere, and in the 

 highest part of the series there are no fossils at all. 



This exposure shows the sands to be very thick, probably 400 ft. at 

 least, and I think that the uppermost part of them is the youngest marine 

 formation in South Canterbury. 



From the sands, concretions, and sandstone layers I collected the 

 molluscs tabulated in column 9 of the table of fossil mollusca, and in 

 addition the brachiopod Pachymagas parki (Hutt.). 



Gordon's Valley. 

 This valley begins near the western end of the exposure of blue clays 

 at Bluecliffs, and passes first of all through the limestone, and then 

 through the blue clays and red sands. The stratigraphy is clear, and 

 shows the relations of the Pareora beds to the limestones. The upper part 

 of the limestone at the head of the valley is more siliceous than usual, and 

 has a fluted appearance due to the alternation of hard and soft layers. 

 There are practically no fossils in the upper part, but in the lower part there 

 are echinoids and crinoids, with a few brachiopods. 



