CARBONIFEROUS AND PEKMO-CARBONIFEROUS ROCKS, N.S.W. 297 



Dr. Woodvvorth after examining a number of the striated 

 boulders iu the Oaney shales at Talihina railway cut con- 

 eludes (op. cit., p. 459) that the striae on the pebbles and 

 boulders are an effect of interstitial motion and displace- 

 ment subsequent to the deposition of the Oaney shale. 

 That is he considers the markings to be pressure striae 

 analogous to "Slickensides." He adds "I saw no stones in 

 the Talihina cut which at the time of my visit struck me 

 as scratched by ice action." At the same time Dr. Wood- 

 worth states that at the area specially examined by him 

 (the Talihina cut) the Oaney shales are highly contorted 

 and crushed, conditions obviously most favourable for pro- 

 ducing rock-pressure striae, but he points out that Messrs. 

 Ulrich and Taff have observed what they considered to be 

 glacially striated boulders in areas where the Oaney shales 

 are disposed merely in gentle undulations. 



Wood worth holds (quite apart from the question as to 

 whether these boulders are glacially striated or not) that 

 the transport of the boulders for 50 miles or more was 

 almost certainly effected by floating ice. 



(ii) Squantum Tillite, Roxbury Conglomerate, Dighton 

 and Seekonk Conglomerates, etc. 



In speaking of the Squantum Tillite described by Messrs. 

 Sayles and La Forge from near Boston, Woodworth states 

 {p. 462):— 



"This presumable tillite bed is possibly of Permian Age, but 

 its association with the underlying conglomerates and similar 

 thick waterworn conglomerates of known Carboniferous (Alle- 

 ghany) age in the Narragansett area point to the correctness of 

 Shaler's theory of the glacial origin of the conglomerates as a 

 whole" 1 



1 U.S. Geol. Surv. Monographs xxxin. Geology of the Narragansett 

 Basin. N. S. Shaler, J. B. Woodworth and A. F. Foerste, Washington, 

 1899. 



