DESCRIPTION OF THE EXPEDITION, 115 
Tamarin Range to the south-west. We then went down to Mahébourg by Grand Port in 
the south-east and examined its neighbourhood, particularly the reefs and smaller islands 
in its vicinity. We passed over the reefs in front of the Bamboo Mountains to Grand 
River 8.E., subsequently returning round the north of the island and visiting Iles aux 
Cerfs, Trou d’Eau Douce, Flacq, and the neighbourhood of Ile d’Ambre, and during 
our return Pamplemousses, where we saw the beautiful gardens of introduced plants. 
The island of Mauritius at the present day gives very little indication of the original 
scheme of the eruptions to which it owes its formation. It may be said to consist of 
three ranges of mountains, each with peaks of over 2000 feet—the Pouce behind Port 
Louis, the Tamarin Mountains to the south-west, and the Bamboo Mountains to the east. 
These ranges together with their enclosed land form a triangle, which includes three- 
quarters of the island as a plateau at least 1000 feet above the sea. The remaining land 
to the north and to the north-east slopes gently into a flat with isolated peaks, such as 
_the Butte aux Papayers, on which the Semaphore Station is situated. While the 100- 
fathom line elsewhere closely follows the shore at a distance of one or two miles, it runs 
out to the north-north-east to a distance of 15 miles from the shore, forming a large 
shallow bank on which are situated a number of islands, Round, Serpent, Flat, Gabriel, 
and Gunner’s Quoin, of which the first-named is 1055 feet high. 
Of the mountains, the Pouce, Bamboo, and a small range to the south-west, of which 
Rempart, 2532 feet, is the highest point, appeared to us to belong to the same period ; 
while the Tamarin Range with its Savane and Riviére Noire sections seemed to have 
been of a more recent formation tacked on to the south-west and masking the otherwise 
fairly regular contour of the central mass. ‘I'he Rempart Range alone appeared to be 
of doubtful formation, possibly an independent eruption; but to the south of Mare 
Vacoa the rock of the Tamarin Mountains appeared to overlie that of the central mass. 
The contour-line of high hills is less marked to the north-east, but there is a clear series 
_ of lower hills with steep slopes between Grand River 8.E. and Nouvelle Découverte. 
The Pouce and Bamboo Mountains are both remarkable for the steep buttresses of their 
outer sides, between two of which the town of Port Louis is situated. 
The central plateau is much broken up by supplementary cones and craters, so that 
its whole structure is masked. Of these the Trou aux Cerfs near Curepipe is well 
marked, but many more appear to exist. The rainfall here is evidently heavy and the 
ground is much channelled by streams, of which Grand River (opening near Port Louis) 
and Grand River S8.E. are the most important. Their gorges and cajions, usually 100 
feet at least in depth with a width of 200 to 1000 feet, break up the country through 
which they pass to aremarkable degree. Those on either side of Réduit are particularly 
noticeable for their depth, but even the smallest stream has a considerable cutting. In these 
streams waterfalls abound, and, as their sides are clothed with dense vegetation, they often 
present scenes of remarkable beauty. The hills on the plateau are generally weathered 
smooth by the rains, though Pouce and Bamboo present a series of jagged peaks of most 
fantastic shapes. Pieter Both Mountain, behind Port Louis, has a head joined by a 
narrow neck to its body, and many others have columns and overhanging cliffs, which 
_ could scarcely have continued to exist in a land much affected by seismic disturbances. 
