THE FORTIETH PARALLEL SURVEY. 499 



THE FORTIETH PARALLEL SURVEY. 



The results of the Fortieth Parallel Survey, in so far as the geological 

 and lithological investigations are concerned, will be chiefly found in 

 the first, second, third, and sixth volumes of the series of publications 

 of that Survey. These volumes will be referred to in the following 

 pages simply as I., IL, III., and VI. 



The tii'st of these, in the order of publication, is Volume III. This 

 bears the title of " Mining Industry," and is chiefly devoted to practical 

 matters connected with mining and metallurgy. It is therefore of 

 minor importance to us in connection with our present inquiry. 



The second in order is that of Professor Zirkel, Volume VI., bearing 

 the date of 1876. This volume is devoted to setting forth the results 

 of a microscopical examination of the lithological collections of the Sur- 

 vey. The next is Volume II. , containing the descriptive geology, by 

 Messrs. Emmons and A. Hague. This volume comprises the whole 

 geological work of the Surve}-, discussed in a geographical order. It 

 bears the date of 1877 on the title-page. Volume I., by Mr. King, 

 entitled "Systematic Geology," was issued last of all, in 1878. It 

 contains, as its title imports, a systematic discussion of all the geologi- 

 cal, lithological, and chemical investigations of the Survey, treated in 

 chronological order, or in that of the geological age of the formations. 

 In the present necessarily brief examination of that part of the work of 

 the Fortieth Parallel Survey which is connected with the subject of the 

 present paper, the relation between Volumes I. and II. should be borne 

 in mind, and will be best understood on reading the following statement 

 by Mr. King : — 



" The purpose of this volume [I.] is to present, as briefly as possible, a sys- 

 tematic statement of the data collected, and the induction we have been able 

 to make. In Volume II. will be found a continuous description of the geo- 

 logical facts observed, treated geographically Uliocver icishes to know 



the structure and details of given features should consult that volume." 



In the first place it will be noticed that Mr. King begins his volume 

 with the consideration of what he calls the " Archfean." Nothing being 

 said in the way of defining what is meant by this term, it would natu- 

 rally be supposed that it was employed with the same meaning as that 

 intended by Professor Dana,* by whom the name Archtean was intro- 

 * See, in reference to this point, farther on, page 547. 



