418 Tramactwns. — Oeology, 



into a dark-brown mineral. The tacbylyte is formed of a pale 

 smoky-brown glass, in wliicb are numerous felspar latbs. Here 

 also tbe olivine has undergone much decomposition, a descrip- 

 tion of which I reserve for another occasion. Its specific gravity 

 is 2-72. 



Below the agglomerates comes a series of thin-bedded 

 greenish-brown sandstones {h) containing fossils, and inter- 

 stratified with ash beds. Below these is a coarse ecoriaceous 

 sandstone, which is underlain by grey current-bedded sand- 

 stones. Then, at the next point, comes a remarkable agglo- 

 merate (rt^) formed of large basalt bombs, the interstices between 

 which are filled up with compact fossiliferous limestone. These 

 bombs vary from one to six, or more, feet in diameter, and 

 some of them on the lower surface curve round those below, 

 showing that they were soft when they fell into their places. 

 Each bomb is encased by a coating of tachylyte about 1 inch 

 thick, which is decomposed in places into reddish-yellow 

 palagonite. The basalt of these bombs is rather coarser in 

 texture than that of the agglomerate first mentioned, and I 

 could detect no olivine with the naked eye ; but under the 

 microscope both the basalts and the tachylytes are much 

 alike. Beyond the agglomerate, in descending order, comes (3) 

 a series of thin-bedded sandstones and clays, dipping 20° N. 

 Next below are (2) coarser scoriaceous sandstones, dipping 

 30° N., and then (1) agglomerate, {a" in section,) which gra- 

 dually changes round to an easterly dip, so as to look nearly 

 horizontal in the clifl". Then comes a fault with a hudc to the 

 north. On the south side of this fault the beds dip 25° S.E. 

 At the top of the clift" are the thin-bedded sandstones and clays 

 (3), underlain by the coarser scoriaceous sandstones (2), so that 

 the downthrow of the fault is to tlie south, or, in other words, 

 it is a reversed fault ; the throw, however, is small. The sand- 

 stones and clays (3) extend to the next point, which is quite 

 low ; and in the following bay all the rocks are obscured by the 

 silt deposit, which here comes down to the sea. The next 

 point is Cape Wanbrow, formed of grey scoriaceous sandstones, 

 dipping 10° S.E. I have given a somewhat detailed account of 

 this section, for I am under the impression that it is at the 

 fault that Mr. McKay supposes an unconformity to exist between 

 his upper eocene and cretaceo-teitiary formations; but, if so, 

 he is undoubtedly wrong. At the same time, I saw no other 

 place where any break occurred at all. 



Past Cape Wanbrow the dip changes gradually to 15° S.S.E. ; 

 then to iS., then to 15° 8.S.W. ; and ultimat'ely to 35° S.W. 

 The grey scoriaceous sandstones of Cape Wanbrow occupy most 

 of this section (PI. XXVI., Section II.), but are overlain by a 

 bed of pale grey tuffaccous limestone, G or 7 feet in thickness, 

 containing minute fragments of coral. This is followed by 



