SAYLES: THE SQUAXTUM TILLITE, 155 



In the tillite of New South Wales, Australia, there is a case very- 

 similar to those just described. The exposure was found by Mr. C. 

 S. Wilkinson in 1879 in Permian, or Permo-Carboniferous tillite. 

 It bears so closely t>n our problem here that it will be well to quote 

 Wilkinson in part. He says: — "In the section exposed in the 

 quarries at Fort Macquaire, Woolloomooloo, Flagstaff Hill, and other 

 places, may be seen angular boulders of the shale of all sizes up to 20 

 feet in diameter, embedded in the sandstone in a most confused man- 

 ner, some of them standing on end as regards stratification and others 

 inclined at all angles. These angular boulders occur nearly always 

 immediately above the shale beds, and are mixed with very rounded 

 pebbles of quartz : they are sometimes slightly curved as if they had 

 been bent whilst in a semi-plastic condition, and the shale beds occa- 

 sionally terminate abruptly, as tliough broken off. Had the boulders 

 of soft shale been deposited in their present position by running water 

 alone, their form would have been rounded instead of angular. It 

 would appear that the shale beds must have been partly disturbed by 

 some such agency as moving ice, the displaced fragments of shale 

 becoming commingled with the sand and rolled pebbles carried along 

 by the currents." (C. S. Wilkinson, p. 194). 



Where the slate fragments appear near the transition-beds the pro- 

 portion of pebbles to matrix is large, suggesting thin ice acting for a 

 short time. There are some sandstone beds intercalated in the tillite 

 which have a strike differing by 8°-10° from the strike of the main 

 body of the slate just above. According to James Geikie (1895, p. 24), 

 this is characteristic of beds intercalated in till. These beds must 

 have dipped to the west when deposited. 



Cleavage is well developed throughout these outcrops. See Plate 9. 



Criteria found: — A, B, C, D, E, F, H, J, K, L, M, N, O. 



Locality 13. Squantiim Head. At Squantum Head about three 

 fourths of a mile north of the exposure just described, there is a massive 

 outcrop of tillite. Strike on the north at contact with the slate X 48 

 E, dip 25° S. These strikes and dips were taken west of a north and 

 south fault line to be described later. The thickness is probably 600 

 feet. The matrix is arenaceous and argillaceous. Boulders, boul- 

 derets, and pebbles are of all shapes and sizes up to three and one half 

 feet in diameter. The proportion of rounded pebbles is larger than at 

 the other Squantum exposure, although angular ones are very common, 

 and the latter show the usual shapes due to glaciation. Dr. Arthur 

 Keith, in the presence of Dr. La Forge and the writer, found one 

 pebble which he considered at the time to be ice worn, and I found 

 a pebble bearing several glacial striae (Plate 10). The pebbles are of 



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