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Art. XXXVIII. — Description of Lava Caves at the " Three Kings" near 

 Auckland. By James Stewart, C.E., Assoc. Inst. C.E. 



(With Illustrations. ) 



[Read before the Auckland Institute, September 20, 1869.] 



It is well known that the various lava beds, near Auckland, are cavernous ; 

 caves are found of various dimensions, both in the older, and more recent lava 

 streams, although in the former, the surface soil, washed in by floods, has 

 partly, or wholly, filled many of them up. 



Many of these known caves are of considerable size, but by far the most 

 extensive in the district, are those, the subject of this paper, situated in the 

 great scoria bed lying to the north-west of the hills called the "Three Kings." 



Some months ago, when a number of the members of this Institute met 

 at these caves, for their exploration, it was seen that they presented some points 

 of interest, and in their relative situation, a little intricacy. As these could not 

 be investigated by a cursory examination, and as it was possible that the 

 result might prove of some value, otherwise than by satisfying mere curiosity, 

 I was induced, in conjunction with Mr. Kirk, to undertake a survey as much 

 in detail as circumstances would permit. The resiilt has shown the relative 

 positions of the caves in this group to be not a little curious, as they branch 

 off from, and underlie each other, to some extent. The survey occupied parts 

 of two days, in all about ten hours. Bearings were taken underground, and 

 marked out on the surface, and regular courses of levels were then run above 

 and below ground, the sectional dimensions of the caves being roughly noted at 

 numerous places. The accompanying plans and sections delineate the positions 

 and levels; I have endeavoured to make the plan as distinct as possible, without 

 the use of colour. (See PI. X.) 



The number of distinct caves in this group, at present explored, is four. 

 They form two sets, of two each. The two pairs have a remarkable resemblance 

 to each other, in some distinctive features. The main pan is marked as the 

 north-western, and the other as the south caves. In both cases, the branches 

 return backwards, at low levels, and they just escape communication with each 

 other. The main cave is generally straight, but of very irregular section, the 

 roof has fallen in many places, and encumbered the floor with large blocks ; 

 at one place, near the mouth, it has broken through to the surface ; it is clear 

 that at this part the original thickness was not much over a foot. The main 

 branch-cave is, for a great part of its length, in its original state, very little 

 stone having fallen from the roof. At the extreme end, however, some has 

 fallen, and much soil has been washed in. 



In section this cave is extremely irregular, but in most places very 

 interesting, from the original form having been preserved, and affording, to my 

 mind, convincing evidence as to the cause of formation. This branch underlies 

 the main cave in a singular manner, having a thickness of rock, between, of 

 eight or nine feet. Both caves have several small branches or chambers. The 

 length of the mam cave of this pair is 351 feet, and of the branch, from its 

 entrance, 209 feet. The widths vary from thirty feet to six feet, and the 

 height from seventeen feet to less than four feet. The south cave is much 

 fallen in, and was not minutely measured. It may have been about 200 feet 

 long, originally, but only about ninety feet (in three divisions) are still 

 complete. At its present most northerly entrance, the branch returns at a 

 low level, and is 1 1 2 feet long. This branch is by far the most perfect of the 

 caves, having, excepting near its entrance, a regular and natural floor, and 

 terminating in a fine chamber with a domed roof. 



The caves seem to be all well ventilated, the air, though extremely 



