98 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. II. 



structure of the interior of the country, and especially of the 

 Alpine districts, has been but imperfectly explored by Euro- 

 peans, no conclusive inferences can be drawn from this nega- 

 tive evidence. 



Beds of limestone, composed of organisms similar in their 

 generic types to those which prevail in certain cretaceous 

 strata wof Europe, appear in a few places along the eastern 

 coast, from near Morakura to Kakaunui : but their relation 

 to the adjacent plutonic and metamorphic rocks has not been 

 ascertained. 



A pleistocene, or modern tertiary blue clay, abounding in 

 shells of species existing in the neighbouring ocean, overlies 

 the limestone at Onekakara ; and is in many places covered 

 by alluvial deposits of gravel, sand, conglomerate, and loam, 

 which form the superficial soil of the vast plains that are 

 spread over the eastern side of the central mountain-chain. 

 On the western shore of the North Island, beds of clay with 

 similar fossil shells occur beneath the ossiferous deposits, as 

 we shall presently have occasion to notice. 



In many places there are alluvial plains of loam, clay, and 

 gravel, overgrown by ancient forests ; and extensive mud and 

 sand-flats, formed by the existing streams and rivers, at their 

 embouchures, and in their tortuous course from the mountain 

 ranges whence they take their rise, till they reach the sea- 

 shore. 1 



OSSIFEROUS DEPOSIT AT WAIKOUAITI. The fossil birds' 

 bones in the Wall-case B, were collected by Percy Earle, Esq. 2 

 and like those transmitted to England by Dr. Mackellar, and 

 the late Col. Wakefield, are for the most part of a dark 

 brown colour, strongly impregnated with tannin, and more 

 or less permeated by phosphate and carbonate of iron ; they 

 resemble in their appearance and state of mineralisation, the 

 bones of the Irish Elk, Mastodon, and Mammoth, &c. dug up 

 from peat-bogs and morasses. They were obtained from 

 a submerged swamp, visible only at low water, that is situated 



1 See " Memoirs on the Geology, and Fossil Remains of Birds of New 

 Zealand, from Notes and Observations by Walter Mantell, Esq." " Geo- 

 logical Journal," Vol. IV. Part I. and Vol. VI. p. 319. 



2 This collection was purchased of Mr. Percy Earle by the Trustees 

 of the British Museum, for 130/. Many of the specimens are figured 

 and described in " Zoological Transactions," Vol. III. pp. 313319. 



