150 A. Holmes & H. F. Harwood — Picrite, Mozambique. 



protuberances of the epidermis into the dermis and that we are 

 looking upon the inner surface of the former. 



There is no sign of ossification, although Marsh 1 speaks " of the 

 osseous dermal covering ". The extent of the epidermal impression is 

 210 mm. long by 200 mm. wide. It consists of hexagonal plates, 

 convex and boss-like, which on their outer surface were probably 

 flat. A group comprising eight of the largest plates covers an area 

 95 mm. long by 68 mm. wide. The central plate of this group has 

 a diameter of 26 mm. The plates surrounding this cluster gradually 

 decrease in size, until they are only 9 mm. in diameter. The plates 

 do not overlap. The integument of Iforosaurus beclrfesii was 

 tuberculate and the lessening in dimensions of the tubercles towards 

 the axillary surface of the arm, where they probably became smaller 

 and rounded, is after the manner of Trachodon and Iguanodon. 



EXPLANATION OF PLATE X. 



FlG. 1. — Impression of a portion of the epidermis from the left ilium of 

 Iguanodon bernissartensis obtained by the author from the Wealden 

 Shales of Brighstone Bay, Isle of Wight, in 1914. 

 ,, 2. — Impression of a portion of the epidermis of Morosaurus becklesii, 

 Mantell, found by Mr. S. H. Beckles in 1852 in the Wealden 

 beds of Hastings, now in the British Museum (No. B. 1870). 



III. PlCRITK FROM THE AMPWIHI RlVER, MOZAMBIQUE. 



By Arthur Holmes, A.B.C.S., D.I.C., B.Sc, F.G.S. (with an Analysis 

 by H. F. Harwood, M.Sc, Ph.D.). 



(PLATE XL) 



ALMOST due west of Mozambique Island, at a distance of about 

 forty-two miles from the sea, the military road from Mosuril to 

 Nampula crosses the Ampwihi Biver, an important tributary of the 

 Monapo. 2 During the dry season the stream is reduced to a string 

 of stagnant pools, separated by long reaches of sand and gravel 

 that here and there are interrupted by outcrops of the underlying 

 formations. Throughout the greater part of its course the Ampwihi 

 flows through a region in which gneisses persist with monotonous 

 regularity, the only variation being that due to occasional intrusions 

 of granite and of still later pegmatite dykes. At the point where the 

 military road crosses the narrow channel a welcome diversion is 

 introduced by the presence of a dark compact dyke about 10 feet in 

 thickness. The dyke appears on the right-hand bank and crosses 

 obliquely to the other side, taking a JS".N.W.-S.S.E. course across 

 the strike of the older rocks. Upstream, about seventy yards to the 

 south-east, the Ampwihi bends to the south-west, so that it returns 

 towards the dyke, which is again exposed across its sandy floor. The 

 dyke was traced by Mr. E. J. Wayland in July, 1911, for a distance 

 of altogether 200 yards, and was examined by Mr. D. Alex. Wray 

 and later by myself during the same year. It is clearly the latest 



1 O. C. Marsh, op. cit., p. 206. 



2 See A. Holmes & D. A. Wray, " Mozambique : a Geographical Study " : 

 Geog. Journ., p. 143, Aug. 1913 (Map, p. 112). 



