14 Transactions. 



a fault is the true explanation of tlie supposed discordance. It is also 

 possible (1) that no fault is present, or (2) that unconformity as well as 

 a fault exists. 



3. Green Island and Brighton. — -The Cretaceo-tertiary age of the Green 

 Island and Brighton coal-seams was naturally assumed by the Geological 

 Survey of Sir James Hector's time. This view was supported by the 

 discovery of Belemnites lindsayi in an impure pebbly limestone almost 

 immediately overlying the Brighton coal. Near Green Island the occurrence 

 of the clearly Tertiary and apparently conformable Caversham sandstone in 

 an horizon high above the coal has led most observers, including the writer, to 

 consider the coal as of Tertiary age, the presence of a belemnite at Brighton 

 being regarded as anomalous. Park, however, explains the situation as 

 due to unconformity between the Brighton and Green Island coals (45, 

 pp. 90, 315-17 ; 50, p. 496). The writer still believes the coals to be of 

 one age, but is now inclined to suppose that the Green Island coal is late 

 Cretaceous, and that there is an unconformity in some upper horizon. 

 Since the Brighton limestone is a beach deposit, its absence from the Green 

 Island district is not hard to explain. The possible stratigraphical break, 

 owing to the amount of clay burdening the surface almost everywhere in 

 the critical area, will be hard to discover. What appears to be an uncon- 

 formity, but only a very slight one, is visible between marl and overlying 

 greensand at the Burnside marl-pit. The greensand contrsins a few poorly 

 phosphatic pebbles. Since, however, phosphatic concretions or beds, and 

 to a smaller extent glauconite, are frequently associated with unconformi- 

 ties (56, pp. 46, 71, 215-17), a careful examination of the phosphatic horizon, 

 which is exposed elsewhere in the Kaikorai Valley, may be recommended 

 as likely to yield evidence of value. 



4. Kaitangata. — -Hutton observed that the upper surfaces of the Kai- 

 tangata coal-seams are in places eroded, and covered by a conglomerate 

 containing pieces of coal (20, p. 106). He does not, however, regard this 

 as evidence of other than local unconformity, of no importance. In 1911 

 Park gives reasons, partly founded on field-work by A. G. Macdonald, for 

 believing that an unconformity similar to that at Shag Point exists be- 

 tween Tertiary and Cretaceous coal-bearing strata, but is not able to report 

 actual contact of the two sets of beds (48, pp. 544-45). Shortly after he 

 reaffirms his position, in order to meet criticism by Marshall (49, p. 318). 

 The writer's own observations show that coal-seams belonging to two distinct 

 horizons occur in the Kaitangata and adjoining districts, as previously 

 stated by A. G. Macdonald, who places both horizons in the Waipara 

 Series (53, p. 1089). Unconformity between these is probable, but cannot 

 be regarded as demonstrated 



Genebal Summaey and Conclusions. 



In sifting the evidence presented by the various writers who have been 

 cited on the previous pages, the chief difficulty arises in separating what 

 was probably seen in the field from what was inferred. While the actual 

 observations demand credit, the inferences made in the literature are by 

 no means of equal value. Thus we find sections drawn without any indica- 

 tion of the blanks filled in by the ideal extension of actual outcrops. In some 

 cases parallel bedded strata are shown as gently diverging immediately 

 below the outcrops, and thus a possibly unwarranted inference of uncon- 

 formity is given support. In one or two instances faults seem to be a 



