368 Transactions. — Geology. 



up into small fragments, which presented sharp fracture-edges, 

 and emitted a " cHnk " like phonolite, or the clang of flint- 

 chips, ^Yhen struck. The width of this band varies in different 

 parts of the division, B, from 2ft. at its widest gibbosities to 

 a seam of such linear dimensions as to be difficult to trace, till 

 a little fm'ther along it widens out, and then tapers off again. 

 \Yithout a closer than the ocular examination which I could 

 alone give it, I could detect little difference in mineral com- 

 position in these two portions. In some places pockets of fine 

 clay in thin laminated plates, intersected by cleavage-lines, ran 

 perpendicularly through the dolerite-bed. These pockets ex- 

 hibited no signs of change from heat, and must therefore be of 

 age subsequent to the dolerite overflow. They occiu'red in 

 the middle or towards the base of the stratum, and in one 

 place extended down to the laterite. After careful examina- 

 tion I detected cracks in the dolerite leading to its surface, 

 by which it was evident that the loess - bed above, while 

 being deposited, had supplied in the form of liquid mud the 

 packing (subsequently slightly compressed) for the fissm"e& 

 and vacuities which had occurred in the lava-flow beneath. 

 This dolerite-bed, which is about 42ft. to ISft. in thickness, 

 rests on the third stratum, C, which must have been at the 

 date of the lava-flow the surface of the ground. The lower 

 surface of A gives no evidence of having sufiered from the 

 effects of heat, so that it is apparent that the dolerite baud is 

 non-intrusive. 



The belt, C, is composed of consolidated clay, presenting 

 many of the characters of the present uppermost bed of loess, 

 and is from 6ft. to 7ft. in depth. The surface-layer contains 

 a few rounded red pebbles, and appears to have suffei'^d a 

 change which looks like fusion for about fin. below its upper 

 surface. It does not present any recognizable evidences of 

 having been deposited under water. It exliibits, on the con- 

 trary, wherever I have examined it, the characteristics of the 

 Banks Peninsula deposit, with the peculiar tubuli seen in the 

 loess, and, as in it, the surfaces of these tubuli are coated 

 with what to the eye (without chemical examination) is a 

 hardened gelatinous silicate, but what may perhaps be an ex- 

 tremely fine deposit of indurated mud. Besides the small 

 tubuli there are many impressions of a large size, varying from 

 iin. to fin. in diameter, whose sides are incrusted with an 

 extremely thin, black, but non-carbonaceous substance, not 

 improbably an iron-compound. These, fi-om their section and 

 irregular form, are evidently the empty moulds of roots or 

 branches. This layer, C, at its junction with the dolerite, 

 has been converted, for depths varying from llin. to 14in., into 

 laterite from the heat of the lava-stream in its incandescent 

 state. 



