Schist on Truk—BRIDGE 
217 
contained in papers by various authors. In 
Tables I and II, Daly credited the reporting of 
amphibolite schist on Truk to Kramer (1908). 
Kramer’s statement is short and explicit and 
may be translated as follows: 
The Truk atoll is a combination of high 
islands surrounded by an atoll ring. Everywhere, 
insofar as I have examined the high islands, I 
found only volcanic rocks, of which feldspar 
basalt was by far the most abundant type. The 
only exception to this is Mt. Vidiboen, a bare 
mountain 275 m. high on the northeastern part 
of the large island of Vela. The eastern slope 
of this mountain rises so gradually that one can 
easily climb it on horseback, in fact a wagon 
road could be built to the summit without great 
difficulty. This mountain is unforested, and its 
rock is amphibolite schist similar to the rock 
on Yap. Dr. Klautzsch confirms my identifica¬ 
tion. 
Stearns (1945, 1946) has drawn the "Sial 
line” so as to include the Caroline submarine 
plateau and all of the high, volcanic islands 
rising above it, on the Sialic or continental side. 
He states (1945: 615) that “The Sial line 
lies a little to the east of the andesite line of 
Gutenberg” and adds that "the line is the prob¬ 
able boundary of the continental platform of 
Australasia” and that "these islands [west of the 
Sial line] might be called Sialic islands from 
the character of their basement, as all are com- 
EXPLANATION 
mm mm mm mm mm Limit Of PaleOZOiC rocks 
mm Limit of Mesozoic rocks 
Limit of. metomorphic or 
Plutonic rocks (revised) 
•••••••••• Proboble boundary 
Melanesian Continent (revised) 
aaMoaa Boundary of metomorphic and plutonic 
areas as formerly recognized 
oooooooooo Boundary of Melanesian Continent 
as formerly recognized 
Fig. 3. Map of the Pacific Ocean south of lat. 10° N., showing the general distribution of various types of 
rock, the probable eastern boundary of the former Melanesian continent, and the true structural boundary of 
the Pacific Basin. (After Ladd, 1934.) 
