13 
materials used by him in the preparation of his thesis entitled 
“ Contributions to the Geology of the Troad.”’ The rock speci- 
mens are 600 in number; the slides, 547. A collection of 100 thin 
sections of typical rocks has been arranged, and descriptions of 
them written out for the use of students of lithology. 
The third part of the ‘Climatic Changes of Later Geological 
Times” was issued just after the publication of the last Annual 
Report of the Museum. That completes the seventh volume of the 
Memoirs. Most of the time of the Sturgis-Hooper Professor has 
been given to the preparation and putting into type of a paper 
entitled “* The Azoic System and its Subdivisions.”’ This paper is 
one of considerable length, and will complete the first volume of 
the Geological Series of the Bulletin. It is the joint work of Dr. 
Wadsworth and the Sturgis-Hooper Professor, and contains a 
pretty exhaustive and critical review of nearly all that has been 
published in this country with reference to the older crystalline 
rocks. This paper is not quite all in type, but can soon be com- 
pleted and issued. 
Dr. Wadsworth has also continued the preparation of his work 
on the Cordilleras rocks, intended to form the eleventh volume 
of the Memoirs of the Museum. The first portion of this might 
already have been issued, had not unaccountable delay in the 
engraving of the plates taken place. He has also published 
numerous shorter contributions to geology and lithology, the 
number of these being between fifty and sixty. Most of these 
are to be found in the Proceedings of the Boston Natural 
History Society, the American Journal of Science, or in the 
weekly publication entitled ‘* Science.” The titles of several of 
these are annexed, in order that their scope may be understood. 
1. Meteoric and Terrestrial Rocks. Science, I. 127. 
2. Keweenaw Point Geology. Ibid., 248. 
3. St. David’s Rocks and Universal Law.  Ibid., 541. 
4, The Microscopic Evidence of a Lost Continent. Ibid., 590. 
5. Ocean Water and Bottoms. Ibid., II. 41. 
6. The Argillite and Conglomerate of the Boston Basin. Bost. Proce. 
Soc. Nat. Hist., X XII. 130. 
7. Some Instances of Atmospheric Action on Sandstone. Ibid., 202. 
8. The Bishopville and Waterville Metorites. Am. Jour. Sci, (3,) 
XXXII. 82. 
