62 Zoological Society. 



silt. The bones collected by Mr. Walter Mantell, among which were 

 the crania and mandibles that formed the subject of Professor Owen's 

 present communication, were all found imbedded in a loose pure 

 sand, formed in a great measure of magnetic iron and minute crystals 

 of augite and hornblende, the detritus of volcanic rocks. This sand 

 has filled all the cavities and cancelli of the bones, but is not in any 

 instance consolidated together: hence the bones are in the most 

 beautiful state of preservation, and the most delicate processes entire. 

 Dr. Mantell conceives that this bed of volcanic sand is a continu- 

 ation of the deposit of sandy loam which occurs at the embouchures 

 of the rivers along the west and east coasts of the North Island, in 

 the localities that yielded the bones sent over by Mr. Williams and 

 Mr. Taylor ; and that in the higher regions of the same river- valleys, 

 the detritus brought down by the mountain-streams from the volcanic 

 chain whence they originate, is unmixed with the clay and silt of 

 the lower alluvial tracts ; for all the streams in these parts of the 

 North Island rise from the lofty ridges of Mount Egmont and Ton- 

 gariro. Dr. Mantell alluded to the fact, that along the sea-coasts and 

 on the banks of the rivers Eritonga, Waibo, &c, there are horizontal 

 terraces of boulders of trap-rocks fifty feet high ; and that the small 

 rocky islands of trachyte off the coast bear marks of wave- action to 

 the height of 100 feet above the present sea-level. He mentioned 

 other facts of a like nature in confirmation of his opinion, that since 

 the Moas existed the surface of the country has been elevated many 

 feet above the level of the sea, and that the present rivers and moun- 

 tain-streams are flowing through channels cut into the ossiferous 

 deposits ; in like manner as the rivers of Auvergne flow through the 

 newer tertiary marls and limestones containing bones of Mammalia, 

 and those of England through the diluvial clay and loam in which 

 are imbedded the remains of the large extinct Pachyderms, the Rhi- 

 noceros, Mammoth, &c. He deemed it probable that the last of the 

 race of Moas were destroyed by the earliest inhabitants of New Zea- 

 land, as the Dodo was finally extirpated by the Dutch colonists of the 

 Mauritius, and the Irish Elk by the early British or Celtic tribes ; 

 but he considered it evident that the bone-deposit was in the progress 

 of accumulation ages ere man inhabited the country. 



2. Drafts for a new arrangement of the Trochilid^;. By 

 John Gould, F.R.S. L.S. Z.S. etc. 



Genus Helianthea. 

 Gen. char. — Rostrum longum, rectum vel sursum aliquanto tendens, 

 cylindraceum. Nares basales, et plumis a rostri basi porrectis, 

 obtectae. Alee mediocres, et validae. Cauda mediocris, et occlusa, 

 paululum furcata. Pedes perparvi. Tarsi admodum breves, et 

 plumis induti. Hallux brevissimus. 



Bill long, straight or inclining upwards, and cylindrical ; nostrils 

 basal and covered with the feathers advancing from the base of the 

 bill ; wings moderately long and powerful ; tail of medium size and 

 slightly forked when closed ; feet very small ; tarsi extremely short, 

 and clothed with feathers ; hind-toe the shortest. 



