110 PROCEEDINGS OF THE WASHINGTON MEETING 



features following the second set. In the case of Mauna Loa, one rift starts 

 near Hilo, on the east coast, and the other from Ka Lae, the southernmost 

 point of the island, and at their intersection the sink of Mokuaweoweo has 

 been formed. South of Mauna Loa are the almost parallel rifts of Kilauea : 

 one from the east of Pahala, on the south shore ; one from near the Olaa Mill, 

 on the northeast, and a third from the line of pit-craters on the east — all 

 intersecting in the sink of Kilauea. 



Extensive faulting, not clearly related to the above tectonic lines, has accom- 

 panied the formation of the islands. On Niihau the eastern portion of the 

 original volcano has dropped out of sight, leaving a line of sheer cliffs. Kauai 

 was originally a volcanic doublet, but the volcanic pile on the northwest has 

 subsided, as is seen in the truncated flows of the Napali cliffs. On Oahu a 

 portion of the Kaala Range may have dropped down in blocks, forming the 

 "pali" (cliff), and cinder cones with some lava flows may have risen between 

 the crags, giving rise to part of the present topography. On the north side of 

 Molokai there is a line of cliffs, rising to a height of 1,000 to 3,500 feet, which 

 bounds the southern third of the original volcano. After the collapse of the 

 northern two-thirds, lava flows built up a small peninsula at the foot of the 

 cliffs, and on this peninsula the leper colony is now situated. 



On Hawaii the breakdown of a portion of the Kahala dome is marked by 

 cliffs on the northeast shore. The west side of Mauna Loa is scarred by a 

 crescentic-shaped fault from Kealakekua southward, along which there has 

 been subsidence on the seaward side. Later flows of lava have run over the 

 cliffs and obscured the fault-line. The crater of Mohokea forms a crescentic 

 depression on the south side of Mauna Loa, but the age of this crater, with 

 respect to Mauna Loa. is uncertain. The south side of the dome of Kilauea, 

 near the sea, from Kalapana nearly to Punaluu, has dropped down in a series 

 of steps over which the later lava flows have poured from far back in geologic 

 time until the last flow of 1S68. The last movement along this shore was a 

 subsidence of from 4 to 7 feet in 1868. 



Presented by title in the absence of the author. 



BANDED GLACIAL SLATES OF PERMOCARBONIFEROUS AGE, SHOWING 

 POSSIBLE SEASONAL VARIATIONS IN DEPOSITION 



BY ROBERT W. SAYLES * 



(Abstract) 



Above the Squantum tillite, which I described last year, there is a series of 

 banded slates about 800 feet in thickness. The manner of transition from the 

 tillite to the slate, with no unconformity, makes it certain that the slate was 

 the result of deposition in waters from the melting of the glacier which formed 

 the tillite. The first of the transition beds are conglomerates alternating with 

 sandstones. Then come sandstones alternating with slates. Here and there 

 it is plain that the ice readvanced over these beds, plowing them up and often 

 dragging upward into the mass thus formed irregular lumps of the clay. Two 

 beds of tillite in the slate itself show the close association of the slate with 



1 Introduced by J. B. Woodworth. 



