Wadsworth.] 432 [October 3, 



Survey has been published and a few advance copies distributed. From this 

 it can be seen that Professor Zirkel's work is looked upon by the Survey as 

 so unsatisfactory that it is to be all done over again! Mr. Hague also fully 

 sustains some of my points by stating that Zirkel frequently mistook 

 triclinic feldspars for sanidin, and that the trachytes of Zirkel in the 40th 

 Parallel Collection are in nearly all cases andesites. (7. c. pp. 11, 12.) 



Mr. Hague further states, in like confirmation of my prior published views, 

 in his " Abstract of Report on the Geology of the Eureka District, Nevada," 

 that granite pophyry and granite are the same ; the difference being purely 

 one of structure, owing to conditions of cooling, rather than dependent upon 

 geological age. (p. 275.) It is further stated by him that the hornblende 

 andesite passes into a "rock which strongly resembles augite-andesite, not 

 only in composition but in microscopic structure," and "judged simply 

 from the hand specimen might properly be classed as augite-andesite." 

 (pp. 281, 282.) Again: " Although olivine is absent from the augite-ande- 

 sites of the district, it will not serve ... as a mineralogical distinction to 

 separate the two rocks, inasmuch as over wide areas of basalt it is wholly 

 wanting. It occurs so irregularly scattered through the rock that any at- 

 tempt to separate the basalts themselves into two divisions on a basis of oli- 

 vine serins futile." (p. 285.) 



It would seem to be now clearly shown that Professor Zirkel did mistake 

 grains in the balsam for crystals in the feldspars, that he made repeated 

 mistakes in the determination of his minerals and rocks, that his propylites 

 are altered rocks, that most of his trachytes belong to other species and fin- 

 ally that his work on the 40th Parallel Collection is so poor that it has now 

 to be done over again. 



This certainly seems a complete vindication of most of the important 

 points of my first paper so far as it relates to the 40th Parallel Exploration, 

 while American lithology is now freed from the chains that were forged 

 in 1875 to bind her. 



Mr. F. W. Putnam gave an account of his summer's explorations 

 of emblematic mounds in Wisconsin and Ohio. In the former 

 state groups of these mounds on the Baraboo River, and at Madi- 

 son, Lacrosse, and Eaton's Farm, Wisconsin River, were de- 

 scribed in detail. Mr. Putnam then illustrated by photograph 

 and map the " Great Serpent Mound," in Adams Co., Ohio. Af- 

 ter careful study he thought that this was probably not a fortifi- 

 cation, but that the resemblance to the form of a serpent might 

 indicate some ancient rites of the builders. The speaker also re- 

 ferred to the famous Highbank Works on the Scioto River, Ohio. 



The f olloAving papers were read by title : On the development 



