Pond. — On the Pottery Clays of the Auckland District. 445 



bore holes put down by Mr. Ninnis at Drury, which show a depth of 69 and 

 64 feet respectively through clays of many colours from white to brown, the 

 seams varying from 1-11 feet in thickness. A few months since I paid a 

 visit to these bore holes, but there is little to see beyond the position in 

 which they were sunk. To obtain a knowledge of these beds, however, 

 it will be found, by skirting the Karaka estuary on both sides from the ferry 

 to Papakura and Drury, that many fine sections can be obtained of the clays 

 in situ, most of them having but little overburden, and stripping will not be 

 so serious a matter as at the bore holes indicated by Dr. Hochstetter. In 

 some places there are 30 feet of clays, in three or four distinct beds, differ- 

 ing slightly in their chemical composition though more or less varied physi- 

 cally. Some of them are very argillaceous, and a few arenaceous, while for 

 variety I know of no district where it can be equalled. After carefully 

 inspecting a number of these sections, I have found nineteen distinct 

 characters, either chemically or physically, of which about twelve will be of 

 value for pottery work. So pure are some of these clays as to require no 

 elutriation, — as they are won from the cutting so they can go to the pug mill. 

 Amongst them there is one terra cotta so rich in colour without any addition 

 or treatment that this alone would be a valuable acquisition, and when we 

 bear in mind the extent to which terra cotta ware is now coming into use, 

 it will be seen that this is no fancy sketch. 



In the future we shall undoubtedly see extensive works located in this 

 portion of the district for the use of these valuable clays, and the working of 

 these beds will be greatly facilitated by a small canal between the Manukau 

 and Waitemata waters. 



Before leaving this part of my subject a few words upon a peculiar clay 

 from Kaitaia may not be out of place. Having received some samples from 

 the north of fine unctuous pipe-clay, I was informed by Mr. Kelly, of 

 Mongonui, that they used a similar clay to make the roads with in that part 

 of the district, and a large sample was forwarded to me, at my request, by 

 Mr. Houston, who states that after spreading upon the roads at first, the 

 horses stick fast, and have great difficulty in making their, way, but that it 

 soon hardens, and, after once becoming so, no amount of rain will cause it 

 to puddle again. 



It has been found by later experience, however, not to have proved so 

 valuable a material for road purposes as was expected. The surface be- 

 coming abraded in the summer, suffers from the strong winds, which 

 remove a good deal, thus rendering it necessary to frequently repair. On 

 examination this material proves to be a diatomaceous earth, the diatoms 

 being intermixed with very finely divided silica. The exceeding minuteness 

 of these fossil diatoms is so great that under a power of 2,000 diameters 



