Hall. — Golden Ridge Graptolites. 413 



The single example of D. caduceus is thejlarge forni, which in Victoria 

 isjnot found associated with D. bifidus, but occurs in higher beds. It has, 

 [ think, been included by mistake. D. bifidus is very common, and juvenile 

 and well-grown specimens occur. Tetragraptus serra agrees with the figures 

 of the form which J. Hall refers to Brongniart's species, and which has 

 been renamed by Miss Elles and Miss Woods T. amii. T. harti resembles 

 T. quadribrachiatus J. Hall, but has only one theca in the primary branch, 

 and is much more slender. The sicula is well shown in the two examples 

 present. Phyllograptus cf. typus comprises several specimens of lanceolate 

 forms of various sizes. 



Age of the Beds. 



Judging by the Victorian standards, and eliminating the two specimens 

 that I regard as intruders, the beds may be arranged in the order given 

 above. They represent the middle and lower series of the Castlemainian. 

 The Bendigonian, characterized by Tetragraptus fruticosus, is with us usually 

 only a few feet below the beds corresponding with those of Butcher's Gully, 

 and it would be of interest to see whether this series is not represented in 

 the locality which has yielded the present series of fossils. The presence 

 of Lancefieldian has been proved at Preservation, as shown by a previous 

 paper to the Institute. 



For convenience, the Victorian divisions of the Ordovician are here 

 given, especially as a recent work on geology coming from a faulty source 

 gives them wrongly : — 



Upper Ordovician. 



/Darriwillian. 



T rv i • • Castlemainian. 



Lower Ordovician -r, , . 



j Bendigonian. 



I Lancefieldian. 



Art. XL VI. — Notes on the Soils of the Wairau Plain, Marlborough. 

 By Leonard J. Wild, M.A., F.G.S. 



[Read before the Wanganui Philosophical Society, 26th October, 1914.] 



The district herein described is about 60,000 acres in extent, and includes 

 some of the richest alluvial soils in the Dominion. The Wairau Plain pro- 

 bably owes its formation to the filling-up of a lagoon by the sediments brought 

 down by the Wairau River. There is no doubt that at a geologically 

 recent period this district was at a lower level than it is at present, and what 

 is now a fertile plain was then an arm of the sea extending up the valley for 

 twelve or fourteen miles from the present coast-line. The neighbouring 

 Awatere Valley was also at a lower level, but was nevertheless a land sur- 

 face, and the Awatere River discharged large quantities of sediment into 

 the sea. A portion of this material, the heavier gravels deposited near the 

 shore, was gradually drifted up the coast, across the mouth of the Wairau 

 arm, and piled up against the cliffs at Cloudy Bay. thus enclosing a lagoon. 

 In this lagoon the sediments of the Wairau River and its present tributaries 

 have been deposited, and even yet the process of filling in is not completed, 

 for in the south-east corner of the district there still remains a portion some 



