PEIMATES FEOM MADAGASCAR. 65 



In several places the bed of the marsh has been uncovered. It is found to consist 

 of a compact layer of volcanic pebbles cemented together by mineral deposits and 

 frequently presenting a metallic sheen. These pebbles apparently form a nearly hori- 

 zontal floor about 3 metres below the present surface. 



Primate remains are found at all depths ; the bones of Hippopotami, Crocodiles, and 

 Chelonians occur chiefly, though not exclusively, in the lower strata. 



Two theories have been proposed to account for the origin of this rich deposit of 

 fossils at Ampasambazimba. The first is that put forward by Messrs. Baron & 

 Mouneyres, who visited the site soon after its discovery. They say in their report : — 



" A notre avis, les osseraents ainsi rencontres et qui sont relativement condenses dans 

 un petit espace, sont les restes d'animaux qui se sont rendus en ce point pendant uu 

 long espace de temps et qui y sont morts, soit de mort naturelle, soit de suite de 

 maladies ou de luttes, le cas de semblable concentration est frequent aux points oil 

 sourdent les eaux minerales." 



It is quite possible that this explanation may account for the presence of some of 

 the remains exhumed at Ampasambazimba. The thickness of the lime-deposits would 

 show that the mineral springs are of ancient date, but there are strong objections to 

 the belief that this theory supplies a sufficient explanation. In the first place, the 

 very large numbers of aquatic and amphibious animals — Hippopotami, Crocodiles, and 

 Chelonians — would seem to lead to the inference that a considerable sheet of water 

 formerly existed at this point. A further objection arises from the consideration of 

 the state of the fossils themselves. In the case of the Lemuroid remains it has not 

 been found possible to reconstitute a single complete skeleton, the bones being- 

 scattered without any apparent order. Thus, for example, a large number of humeri 

 and several radii of Megaladapis have been discovered, but not a single femur. 

 Considerable numbers of femurs and tibio-tarsi of various species of ^pyornis have 

 been found, but comparatively few vertebrae, and only one imperfect skull. In describing 

 the method found necessary in exhuming the bones in the alluvial deposit at Lambo- 

 harana on the south-west coast Dr. Grandidier says : — " The bones are not at a great 

 depth, never more than two metres; they are encased in a compact humus, which 

 during the work is rapidly transformed into mud on account of the water which 

 immediately invades the diggings as the operations are continued. This is, indeed, the 

 chief obstacle to the methodical carrying out of the search, and which, both in the 

 western region and in the centre of the island, prevents the finding of complete 

 skeletons, for one is obliged to feel for the submerged bones either with a spade or 

 with the hands or feet, according to the depth at which they are situated under the 

 water, and to draw them out one by one." 



If the above description were applicable to the method employed at Ampasambazimba 

 the argument as to the scattered and incomplete character of the remains exhumed 

 would not have much weight ; but, as I shall presently describe, it has been possible 



