THE GREAT MARLBOROUGH CONGLOMERATE 363 



fans, the material of which was a mixture of angular blocks from 

 near at hand and well-rolled pebbles brought from a distance. 

 The presence of blocks with the facies of the underlying series is 

 thus explained. The bowlders of volcanic rock, while they have 

 not their equivalent in the immediately underlying series, are of 

 the same type as the known volcanics of the Amuri Series which 

 occur a few miles to the northwest in the Awatere Valley,^ and it is 

 quite possible that they were present in that portion of the Amuri 

 Series that has been denuded off the site of the Kaikoura Range. 

 The absence of the coarse-grained intrusive rocks of the Kaikoura 

 Range, even if these should prove to be absent everywhere from the 

 conglomerate, is not remarkable, and does not necessarily indicate 

 that the date of their intrusion was later than that of the accumula- 

 tion of the conglomerate. It indicates rather that the rocks of the 

 present Kaikoura Range, which, it must be remembered, owes 

 its present elevation to later folding, had not then suffered the 

 enormous denudation which has exposed the intrusions. It is 

 possible that the bowlders of volcanic rock in the conglomerate 

 represent the more superficial equivalents of the deep-seated 

 intrusions now exposed in the range. 



The foregoing hypothetical explanation refers only to the strip 

 of Great Marlborough Conglomerate following the line of the 

 Middle Clarence Valley. The writer believes that the outcrops near 

 the coast may be similarly explained, but further study of them is 

 required, and an extension of the hypothesis to cover all occurrences 

 of the conglomerate is beyond the scope of this paper. 



several places in the northeast end of the Middle Clarence Valley, attains a con- 

 siderable thickness, but is thin as a rule. The pebbles in the fanglomerate, on the 

 other hand, seem to be uniformly abundant, indicating a uniform source of supply. 

 The necessity arises also of accounting for the presence of the rounded pebbles in the 

 transition beds from the Grey Marl to the fanglomerate, the deposition of which 

 must have been contemporaneous with the beginning of movement on the fault plane, 

 that is to say, must have preceded the exposure in the fault scarp of the deeply buried 

 Cretaceous conglomerate. These pebbles at least must have come from the old land. 

 ' McKay, op. cit. (iSgo), pp. 184-85. 



