6 



BULLETIN OF THE 



Pages 371 - 801 of a publication previously mentioned* is devoted to 

 the publication of the reports of Dr. C. T. Jackson and his corps. This 

 document is one of the curiosities of geological literature, — a vara avis. 

 It was printed in such a manner that in many cases it would be very 

 difficult, if not impossible, to determine who were the autliors of the 

 difierent parts of the text, were it not for the fusiUade all along the line. 

 Dr. Jackson gives (pp. 477 - 479) some account of his first knowledge 

 of tlie iron ore (1844) in this district, but it seems that he never visited 

 the region himself Dr. John Locke, iu his field-notes for 1847 (l. e., pp. 

 572- G05), describes the rock of Prcsque Isle as " a light-green trap, re- 

 ticulated with white veins near the junction of the sandstone, with which 

 the trap is apparently interfused." He also describes the iron region to 

 some extent. He considers that the trap rocks are frequently interfused 

 with the metamorphic cues in the district, and states that certain quartz 

 veins "deserve close examination for gold, silver, and other rare metals. 

 Veins of this description, if they prove important, can undoubtedly be 

 found in the metamorphic rocks." 



It is well known that the early explorers had tc contend with very 

 great difficulties in their work in this region ; but probably none ever 

 suffered such aggravation of spirit as did Dr. Locke, when, on July 27, 

 1847 his compass ran wild and its poles stood seventeen feet and eight 

 inches apart, unless it was when he found his provisions were only a few 

 sticks of wood and a bucket of bean soup.t Mr. J. W. Foster, m his 

 report to Dr. Jackson, dated May 26, 1849 (1. c, pp. 773 - 78.5), gives 

 a description of the iron region, as studied by him in 1848. He regards 

 the iron ores as sedimentary deposits. " These bods, so for as I have 

 observed, present a marked similarity in mineralogical characters, and 

 derive their origin from common causes, and those were aqueons. The 

 jointed structure and waved stratification of some of the beds prove that 

 ir^neous causes have operated, since their deposite, to modify and change 

 their character." (p. 776.) « Here, they certainly bear upon their sur- 

 faces strong marks of thcii mechanical origin. They are regularly 

 stratified, and often contain thin scams of silcx in mmuto grams, so 

 that a specimen, on its cross fracture, resembles ribbon-jasper. The 

 lines of stratification can readily be distinguished from those of lamma- 

 tion. Like the slates, they are often found contorted and wrinkled, and 

 the same facts could be adduced in both cases to prove their common 

 origin 



n 



(p. 770.) This description belongs, for the most part, to the 



* Senate Documents, lat Soss. 31st Cong., 1849-50, ITI. 371-935. 



t Senate Documents, 1st Sess. 30th Cong., 1847-48, IT., Doc. 2, p. 190. 



r-'' P 



