230 MAYOR— THE REEFS OF TUTUILA, SAMOA. 



corals are slow to gain a foothold except in the immediate vicinity 

 of densely clustered living coral heads. 



The inner ends of the bays of Tutuila were partially filled in by 

 delta-plains when the sea stood higher than at present, but these 

 have shared in the general emergence of about eight feet, and thus 

 their swamps were drained, only a few small recent mangrove 

 swamps being now found as at Massefau, Leone, Vatia, and several 

 places along the shore of Pago Pago Harbor, as at Aua and Utelei. 



During the past fifty years or more, no severe hurricanes have 

 passed over Tutuila, but there is abundant geologic evidence of their 

 presence in recent times. Thus the reef flats near the mouth of 

 Pago Pago Harbor bear many large erratic coral masses which have 

 been torn off from the edges and tossed up upon the platform of 

 the reef. One of these fragments at the edge of the reef off the 

 southern end of Aua village in Pago Pago Harbor is so large that 

 the Harbor chart records it as " Coral Block 3 ft." Also at Vatia, 

 Laulii, and many other places, there are masses of recently broken 

 coral driven up 10 feet above high tide level and now lying cov- 

 ered with moss under the dense shade of the largest forest trees 

 which have grown over them since the hurricane tossed them up 

 as wreckage upon the desolated shore. In ancient times we see 

 that Tutuila was partially surrounded by a barrier reef which 

 had grown upward along the seaward edges of a platform of 

 marine erosion which had become submerged by the subsidence 

 of the island itself. Fringing reefs were at the same time grow- 

 ing outward from the shore and in many places, especially along 

 the northern coast had fused with the barrier reef. Then due 

 to a rising of the sea level combined with continued subsidence of 

 the land mass these old reefs were drowned, and for a long period 

 we find the island unprotected by any reefs while the sea cliffed the 

 shores not only at the promontories but well within the drowned 

 valleys. Finally the sea level sank about 20 feet below its highest 

 level and after this, in modern times, a fringing reef began to grow 

 outward from the 'shores and has now attained a maximum width 

 of not over 1,000 feet. Also in modern times coral patches began 

 to grow upward upon the Taenia and Nafanua Banks in places 

 which were probably islands well above sea level at the time when 



