THE FORMATION OF ZANZIBAR. 137 



39° 32' 5'. French travellers assume a max. 

 length of 83 kilometres, and a max. breadth of 

 33. The capital (S. lat. 6° 9' 6") corresponds 

 in parallel with the Pernambucan province to 

 the west and with Java and central New Guinea 

 to the east. The corrected longitude (laid down 

 by Captain Smee in 1811 as E. lat. 39° 15') gives 

 a difference of Greenwich time 2 h - 36 m - and 56 s -. 

 From Southampton round the Cape the run 

 is usually laid down at 8500 miles, via Suez 

 6200. The Lesseps Canal has shortened the dis- 

 tance from Marseille by 2000 leagues, and thus 

 has placed Zanzibar within 1600 leagues of the 

 great port — in fact, about the distance of the 

 Gaboon ex-colony. 



The formation of the island is madrepore, 

 resting upon a core or base of stratified sand- 

 stone grit, disposed in beds varying from 1*5 to 

 3 feet thick. The surface gently inclines towards 

 the sea, and the lines of fracture run parallel 

 with the shores. Three distinct formations oc- 

 cur to one crossing the breadth. 1 The first is a 



1 Dr Ruschenberger, I know not on what authority, says 

 that the island is undulated and crossed by three principal 

 ridges, whose most elevated points are 500 feet high. My in- 

 formation, derived from hearsay, however, not from actual 

 inspection, assures me that the waves of ground are disposed 

 north and south. 



