PRIMATES FEOM MADAGASCAR. . 67 



down in the alluvial deposit forming on the floor of the lake. This view seems the 

 more probable in that numerous remains of JEpyornis have been found actually 

 embedded among the water-worn pebbles where the bank of shingle shelves down at 

 this point to form the floor of the basin. 



It will be seen on referring to the contour-map to what an extent volcanic action 

 has taken place in the region drained by the Mazy in the higher reaches of its course. 

 It is certain, not only that the country was formerly much more wooded than at 

 present, but that large areas were covered by lakes which have since been drained. 

 Judging by the recent appearance of some of the streams of lava and the very irregular 

 character of the surface in this volcanic region, it is quite possible that considerable 

 tracts of forest may have been actually devastated and the debris of the flora and fauna 

 carried down and deposited in the lake at Ampasambazimba. A curious incidental 

 confirmation of the belief that these animal remains were deposited in water is afforded 

 by the fact that very many bones, notably the pelves of giant Chelonians and skulls of 

 Palwopropithecus, show the imprints of Crocodiles' teeth. The photograph of a skull 

 of Fala^opropithecus maximus shown in Plate XII. fig. 1 will illustrate this fact. 



It has been possible in the case of the fossils at Ampasambazimba to employ a 

 method of excavation which has great advantages over that described above by 

 Grandidier. It will be noticed on reference to the map that a small affluent joins 

 the Eiver Mazy at the point where the latter turns abruptly southwards before skirting 

 the edge of the marsh. An ancient native watercourse indicated where a part of the 

 waters of this streamlet had been led round the head of the marsh for the purpose of 

 irrigating the rice-fields, traces of which may still be seen. By deepening and widening 

 this watercourse and continuing it by a broad channel down to the edge of the marsh, 

 it was found possible to conduct a considerable volume of water right through the 

 fossil diggings. It was necessary at the same time to provide an outlet for this stream 

 at the southern edge of the marsh. Here a formidable obstacle presented itself in the 

 broad barrier of compact travertin which has already been referred to as separating 

 the fossiliferous deposits from the present course of the river. By the help of native 

 workmen and a considerable expenditure of dynamite, a channel some 40 metres long 

 and about 2 metres deep was at length cut. It was now possible to expose a long 

 vertical section of the marsh, and a line of workmen could be employed throughout 

 the day working against the vertical wall thus formed ; while each evening the earth 

 thus carefully examined could be got rid of by sending it down the stream into the 

 river below. By this method the smallest and most fragile articles can be obtained 

 intact. In one instance, a small bird's egg was found unbroken at a considerable depth 

 in the compact black earth. The percentage of the breakages of valuable specimens 

 has thus been greatly reduced, and one can feel certain, with a company of trained 

 W'orkers, that nothing of importance will escape their scrutiny. The accompanying 

 photographs (text-figs. 4-8) will sufficiently supplement the description here given of 

 this method of excavation. 



VOL. XVIII. — PART II. No. 2. — May, 1908. l 



