ON THE RELATIONS OF THE GREAT MARLBOROUGH 

 CONGLOMERATE TO THE UNDERLYING FORMA- 

 TIONS IN THE MIDDLE CLARENCE VALLEY, NEW 

 ZEALAND 



C. A. COTTON 

 Victoria College, Wellington 



CONTENTS 



Introduction 



Conclusions as to the Nature and Relations of the Conglomerate 



Conformable Relation to the Underlying Beds 



Composition 



In the Gorge of the Dee 



In the Gorge of the Mead 

 Fluviatile Origin 

 Hypothesis to Account for the Peculiar Features of the Conglomerate 



Significance of Faults in the Conglomerate 

 Geological History 



INTRODUCTION 



McKay, in describing the geology of the Cape Campbell dis- 

 trict in 1877, mentioned ''conglomerates, composed in chief part 

 of well-rounded bowlders, but having a large percentage of angular 

 blocks of great size, so that on the surface they often present the 

 appearance of old Morainic accumulations." His description 

 continues as follows: ''A great variety of rocks are represented in 

 these conglomerates — -old slates and sandstones, and even crystal- 

 line rockc from the inland ranges; volcanic rocks from the Amuri 

 group; green sandstone from the Saurian beds; and great masses 

 of Amuri limestone — -as before mentioned large bowlders of con- 

 glomerate from the Awatere beds, as well as limestones, sandstones, 

 and shell conglomerates belonging to the same."' In the section 

 accompanying McKay's report^ the deposit is represented as 

 superficial, lying on the upturned edges of the "Saurian beds" 



' A. McKay, Geol. Siirv. of N.Z., Rep. Geol. Expl. during 1874-76, p. 190, 1877. 

 ^ Op. cit., BB, opp. p. 188. 



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