390 PROCEEDINGS OP WASHINGTON MEETING. 



Similar planes appear in the micaceous quartzite, just to the west, which underlies 

 the more calcareous division of the " calciferous mica-schist," and thus it is plain 

 that the Thetford argillite is older than the mica-schist. 



Last of all, other illustrations appear in Hanover and Lebanon, New Hampshire, 

 in the "Coos quartzite," a rock lithologically like the Lower Cambrian quartzite 

 on the west flank of the Green mountains. 



We can therefore say that the majority of the so-called strata dips of these rocks 

 are cleavage planes, and that the original structure has been commonly obliterated. 

 The importance of these discoveries consists in the confidence given to our belief 

 in this obliteration of the strata. So long as it was uncertain what the truth might 

 be, it was difficult to be satisfied with the sections protracted. 



It is worthy of note that the revision of the dips has thus far not affected our 

 expressed conclusions respecting the relative ages of the several terranes of the 

 district. 



Remarks were made by A. C. Lane. A brief abstract is published in 

 Science, volume 5, January 15, 1897, p. 86. 



The third paper was entitled — 



UNCONFORMITIES OF MARTHAS VINEYARD AND OF ROCK ISLAND 



BY J. B. WOODWORTH 



Remarks were made by W. B. Clark, David White, and G. K. Gilbert. 

 The paper is printed as pages 197-212 of this volume. 



In the absence of the author, the next paper was presented in abstract 

 by Mr Gilbert, its place in the program being held by special vote : 



CEMENTING MATERIALS OF THE TERTIARY SANDS AND GRAVELS OF WESTERN 



KANSAS 



BY ERASMUS HAWORTH 



A discussion of this same subject, but in a different form, is given in 

 volume ii of the University Geological Survey of Kansas. 



The following paper was then read : 



THE WORK OF THE UNITED STATES GEOLOGICAL SURVEY IN THE, SIERRA 



NEVADA 



BY H. W. TURNER 



Remarks were made by the President, J. E. Wolff, C. D. Walcott, and 

 the author. 



