270 C. L. Whittle — Ottr elite-hearing Phase of the 



white (gray) furnished by the mixture of the pure fundamental 

 red and its pure complement ; a number was obtained ex- 

 pressed in terms of the luminosity of white card-board, and 

 the same operation was performed for complementary yellow- 

 green and purple as well as for yellow and blue discs. With- 

 out laying much stress on the results obtained, it can at least 

 be said that they did not render improbable the idea that these 

 pairs all furnished equal grays when united. To settle this 

 problem experimentally would of course require a considerable 

 amount of elaborate work, if indeed it is at present capable of 

 such solution. 



I shall be glad to furnish without cost samples of colored 

 paper with coefficients to those who are particularly interested 

 in these matters. 



Art. XXXV. — An Ottreiite-bearing Phase of a Metamorphic 

 Conglomerate in the Green Mountains / by Charles Livy 

 Whittle. 



[Published with permission of G-. K. Gilbert, Chief Geologist, TJ. S. Geological 

 Survey.] 



The geological position of the limestone and quartzite of 

 the Rutland valley has lately been definitely determined, the 

 limestone paleontologically and the quartzite stratigraphically.* 

 Occurring next below the limestone the quartzite is the northern 

 continuation of the Clarksburg-mountain quartzite in Massachu- 

 setts in which Walcott has- found the Olenellus fauna charac- 

 teristic of the Lower-Cambrian horizon. About one mile north 

 of Rutland village, in Vermont, Dr. Wolff and Dr. Foerste were 

 fortunate enough to find Lower-Cambrian fossils in a siliceous 

 limestone that lies superjacent to the quartzite. Northeast of 

 Rutland the quartzite is found associated with a sandy, phyllitic 

 schist that belongs to a series of metamorphosed elastics having 

 a vitreous quartzite or conglomerate at its base. This whole 

 series, barring the Lower Cambrian quartzite and limestone, has 

 been subjected to the most intense dynamic action. The se- 

 quence of the different members of the series is in many regions 

 hopelessly obliterated and confused by the mountain-building 

 forces that have produced new structural planes and a new min- 

 eral composition ; and have additionally complicated the geo- 

 logical order of succession by sharp folding, as a rule too much 



*On the Lower Cambrian Age of the Stockbridge Limestone. Bulletin Geol. 

 Society of America, vol. ii, pp. 331-338. 



