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of prepared slices ; in a specimen gathered there was 

 a fossil in appearance something like a pipe-coral, 

 though it was not a coral at all. Possibly it was a 

 lichen. It would be difficulty to say of what age the 

 sinter deposit is, as equisita are found from the Car- 

 boniferous system upwards to the Post tertiary ; but 

 it may be mentioned^that equiseta of the largo diameter 

 of some of these fossils are certainly not found in 

 Imerina at the present day. There seems, so far as I 

 know, to be in central Madagascar, only one, or at 

 most two, species of equisetum, both of which are 

 much smaller in diameter than the fossil specimens 

 And, moreover, these two species are exceedingly 

 rare, whereas the fossil in the sinter are extremely 

 abundant, so much so that these equiseta seem to have 

 formed a prominent characteristic of the ancient flora 

 of the neighbourhood— Another pond, within about 

 a quarter of an hour or twenty minutes distance from 

 the sinter deposit, was reached to the north east of 

 the deposit, was reached to the north of the pond, 

 near Antanimena. Here was what appeared the lar- 

 gest crater seen as yet. It was a very perfect beautiful, 

 oval crater, filled with water in which from on side to 

 the other was an abundance of the harefo rush. To 

 the west of this again, on the next hill, there was, it 

 is said, another similar basin-shaped depression, but 

 without water. The sixth and last crater was then 

 reached much smaller in diameter than the others but 

 deeper. Scoriee were lying about in abundance on 



