Thomson. — Geology of Middle Waipara and Weka Pass District . 327 



Cockburn Hood in 1870 gave a description of the locality and the rocks 

 from which he obtained his collection. 



Following Cockburn Hood"s successful search, Hector in 1868 sent R. L. 

 Holmes to collect for the Colonial Museum, and he obtained a " fine series 

 of specimens," principally from a tributary of Boby's Creek (c/. Hector, 

 1869, p. xi). Drawings of these, forwarded by Hector to Owen, enabled 

 the latter in 1870 to add two further species to the fauna — viz., Plesiosaurvs 

 crassicostatus and P. hoodii. Hector in 1874 described other species from 

 Holmes's collection, and mentions also a specimen collected at Boby"s Creek 

 by W. T. L. Travers. 



In 1872 von Haast employed A. McKay to collect for the Canterbury 

 Museum, and it was his success in this task that later led to his employ- 

 ment in the Colonial Museum and Geological Survey. McKay subsequently 

 collected further saurians for the Colonial Museum in 1874, but in 1877 he 

 reported that all the more accessible specimens had been secured and 

 further collections could only be made at considerable labour and expense. 

 Nevertheless, in 1891 he was successful in recovering a specimen which he 

 had first seen in 1874, but which had been for some years covered up by 

 river-shingle. McKay's experience, as stated in 1892, was that '' nearly all 

 the boulders [concretions] that contain bones split in falling from the cUifs, 

 or in being shifted along the river-bed, and it is never worth while to open 

 a boulder so situated that does not show the presence of bones." 



In 1876 or 1877 Hector exchanged " 250 specimens, fossil Reptilia of 

 New Zealand " with the Trustees of the British Museum, and descriptions 

 of these were included by Lydekker in the Catalogue of Fossil Rejytilia and 

 Amphihia in 1888 and 1889. Hutton in 1894 described one of the speci- 

 mens collected by McKay for the Canterbury Museum in 1872. Since 1892 

 no fresh collections of saurians from the district have been made, but the 

 interest of geok)gists has been sustained for another reason— namely, the 

 apparent conformity of the beds containing the saurians with others con- 

 taining a purely Tertiary fauna. 



The first general account of the geology was given by Hector in 1869, 

 who noted that the saurian beds were intimately associated with, but 

 probably underlay, blue and grey marly sandstone, sometimes passing into 

 chalk, and were in turn underlain by white and brown sandstones containing 

 coal-seams, and correlated with the Wealden. These three formations were 

 covered unconformablv bv Miof'ene white and yellowish calcareous sand- 

 stone, in parts composed altogether of cup-shaped Polyzoa, and by reddish 

 limestone, composed of comminuted shells. On these Miocene rocks rests 

 Pliocene blue clay with beds of sand and gravel containing many existing 

 species of marine siiells. Hector gave no account of the structure, but 

 stated his belief that the underlying " Triassic " rocks had been denuded 

 into hills and valleys long prior to the Tertiary period. As Hutton pointed 

 out in 1885, Hector did not distinguish between the " grey marl," the Weka 

 Pass stone, and the Amuri limestone, but considered them all as a '' blue- 

 grey marly sandstone sometimes passing into chalk." The unconformity 

 here postulated Hector always adhered to, the lower group becoming later 

 his Cretaceo-Tertiary formation, and the middle (Miocene) his Mount Brown 

 beds, or Upper Eocene. 



The next account of the district, by von Haast (1871), was based on a 

 detailed survey of the Middle Waipara part of the district, carried out under 

 Hector's direction for the Colonial Geological Survey, and was accompanied 

 by a map. Von Haast gave a detailed account of the beds in the Waipara 

 River and in Boby's Creek, the most detailed account yet given so far as 

 the beds below the Amuri limestone are concerned ; but, like Hector, he 



