Thomson. — Geology of Middle Clarence and lire Valleys. 



325 



lowest flint-beds seen are of a lenticular character, in layers of 8 in. 

 to 18 in., the beds swellinsj ont around the flint lenticules in such a 

 way that the surface of the beddins-planes is irregular (see Tliomson. 

 1916, pi. ii, iii). The outer layers are composed of crystalline dolomite. 

 Higher up the flint-beds become less lenticular and the exteriors are hard 

 chalky limestone, layers of which also appear between the layers contain- 

 ing flint. Then follows a considerable thickness of hard chalkv limestone 

 with flint-beds subordinate, and finally another series consisting dominantly 

 of flint-beds, the top being 1,410 ft. above the lowest observed beds. Above 

 this flint is of relatively rare occurrence, but is by no means absent from 

 the chalky limestones. The marly limestones in part consist of the thin- 

 bedded alternations of chalky and marly limestones above described. No 

 traces of fossils were observed in any of the above beds. 



Limhurne Gorge. — The Amuri limestone in the left branch of the Limburne 

 consists of flint-beds at the base, then hard chalky limestone, marlv lime- 

 stone with chalky bands, and hard chalky limestone above. The uppermost 

 beds are obscured by slips, and the top band of marly limestone and the 

 Weka Pass stone are probably }»resent, as in the Mead and the Dee. 



Dee Gorge. — The flint-beds and the chalky and marly limestones succeed 

 one another in the same order as in the Limburne and the Mead, and the 

 thickness is probably about the same. The uppermost limestone, the Weka 

 Pass stone, is a grey-white argillaceous limestone, without the tvpical 

 cuboidal jointing of the Amuri limestone. No fossils were observed. 



The flint lenticules at the base are ])resent in beds averaging 8 in. thick, 

 but some are as much as 2 ft. thick where the lenticules occur. The 

 crystalline dolomitic rock is not abundant, and is most developed where 

 the flint lenticules are thickest and most irregular. Tlie great majoritv 

 of the flint lenticules in the lower beds, and all in the upper beds, are not 

 accompanied by crystalline exteriors, but by hard, flinty, chalky limestone. 

 Mr. B. ('. Aston has made the following analyses of specimens from this 

 localit}^ : — 



Chalh Range. — McKay estimates the thickness of the Amuri limestone 

 and Weka Pass stone in the Chalk Range at 2,500 ft., of which the lower 

 1,000 ft. consists of flint-beds. The middle beds he describes as soft chalk 

 marls, followed by more compact flaggy limestones, whicli in the liighest 

 peak of the range contain beds of a green colour. Above these are beds 

 resejnbling the Cobden lijuestone, witli large radiating fan-shaped fucoids. 

 The latter is followed by a calcareous sandstone, the Weka Pass stone, 

 and these two uppermost beds contain layers of greensand and quartz 

 sand alternating witli the more calcareous strata. It should be observed 



