360 Geology of 



agglomerate was passed, which was so loose and full of water that the- 

 ground had at once to be heavily timbered. All the cavities in the 

 lava are lined with sphserosiderite, on which crystals of calcareous spar 

 have been deposited. At 40| chains on the same side, in a bed of 

 laterite, four feet above the floor of the tunnel, a small spring was 

 struck, drying up a few months after ; 35^ chains from the Lyttelton 

 end, the lava-streams, when first passed through, were so wet that the 

 workmen could scarcely continue the work. In these streams, all the 

 cellular cavities were either lined with sphserosiderite or filled with 

 ealcite. Sixteen chains from the Lyttelton entrance, in the agglo- 

 merate bed Xo. 228, and from a fissure reaching from the roof of the 

 tunnel, a copious spring flows which has a constant temperature of 

 65*20 degrees Pahrenheit, consequently 12*20 degrees above the mean 

 temperature of Christchurch — about 53 degrees. Several eels have 

 been caught near this spring, in the drain which runs from here to the 

 mouth of the tunnel. There being no connection with any other 

 water-course, these eels must have ascended by the spring; they 

 belong to the species Anguilla AucMandii Rich., and have properly 

 developed eyes. During the construction of the tunnel, it was 

 frequently observed in the north or Heathcote end, that the water 

 rose in the floor before a south-west gale, and subsided before the 

 gale lulled ; no observations could be made to ascertain whether the 

 state of the tide had anything to do with this. The height to which 

 the water rose was somewhat under half an inch. After the earth- 

 quake of August 17, 1SGS, this spring in the tunnel increased to such 

 an extent that it laid the rails slightly under water ; after a few day* 

 it decreased again to its former volume. 



