. Transactions and proceedings of the New Zealand Institute . gravels and cements (which havebeen worked in places), sandstones, and, further north, limestones. Thebase of the series is occupied by coarse greywacke breccias, well exposed inthe BuUer Gorge, on the east flanks of the Paparoa Range. The rock seriesthus described as exposed in the Reefton district is typical of the greatcoal-bearing series of the West Coast, whose age is still a matter of have been classed by Hector and McKay as Cretaceo-tertiary,J butthe Hmestone fossils indicate a much younger age. Whatever their age,
. Transactions and proceedings of the New Zealand Institute . gravels and cements (which havebeen worked in places), sandstones, and, further north, limestones. Thebase of the series is occupied by coarse greywacke breccias, well exposed inthe BuUer Gorge, on the east flanks of the Paparoa Range. The rock seriesthus described as exposed in the Reefton district is typical of the greatcoal-bearing series of the West Coast, whose age is still a matter of have been classed by Hector and McKay as Cretaceo-tertiary,J butthe Hmestone fossils indicate a much younger age. Whatever their age,they rest with marked discordance on the older rocks, and are also deeplyinvolved in thestructure of the ranges on which they occur, as is well seenin Murray Creek. The Inangahua Valley is occupied by gravel terraces of Pliocene orPleistocene age, and by recent gravel-deposits. The gravels, both in themain valley and in the tributary streams, have yielded a considerablequantity of alluvial gold, and are even yet in places profitably worked bysmall Devonian Pocks Fig. I.—Sketch Section across Reefton Goldfield. The above sketch section across the district from west to east indicatesthe geological structure. * A. McKay, Geology of Reefton District,.Reps. , 1882, p. hoc. ciL, p. Lor. p. 140. 88 Transactions. Dykes. |The granitic rocks are penetrated here, as elsewhere on the Coast, bynumerous basic and semibasic dykes, inckiding varieties ■ of diorite, por-phyrite, camptonite, and similar types. The slates are also intruded by a series of dykes which, so far as yetknown, are exclusively of diabase. The outcrops are difficult to locate,owing to the extensive alteration which the dykes have undergone, someof them being slightly schistose. They have generally been exposed inmine-workings only, and, as many of the mines are now closed down,observations cannot readily be made. They have been found in theSpecimen Hill, Inglewood, and Keep It Dark
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