AMERICAN GEOLOGY DECADE OF 18(50-1869. 



511 



(2) the pebbles themselves had been in a more or less plastic state; 

 otherwise any attempt at change in form would result only in frac- 

 ture and comminution. The clean manner in which the pebbles were 

 cut by joints was thought also to indicate a condition of plasticity. 

 The flattening and distorting force was thought to have operated later- 

 ally, and the jointing regarded as due to some polarizing force acting 

 upon soft materials, a simple inspection of the rock in place being suf- 

 ficient to satisfy anyone that no mechanical agency would alone be 

 sufficient to produce the phenomena. Appl} T ing the same method of 

 reasoning to the conglomerates of Vermont, he came to the conclusion 

 that these, too, had undergone metamorphism, giving rise to schists 

 and gneiss, and that, indeed, granites and syenites might result from 

 the metamorphism of stratified rocks. The chemical details as worked 

 out would naturally not hold in their entirety to-day, and of course 

 the idea of a polarizing force would be no longer seriously considered; 

 but the fact remains that this paper, as a 

 whole, marks a long stride in advance along 

 the line of metamorphism, and for its time 

 was comparable in its importance with the 

 later work of Lehmann on the crystalline 

 schists of Saxony." 



B}' an act of the legislature approved 

 March 1(5, 1861, Eze'kiel Holmes, of Win- 

 throp, Maine, was commissioned, under the 

 direction of the board of agriculture, to 

 make a scientific survey of 

 the State. C. II. Hitch- 

 cock, then of Amherst, Mas- 

 sachusetts, and a son of Dr. Edward Hitch- 

 cock, was commissioned geologist, while 

 George L. Goodale served as botanist and chemist, C. Houghton as 

 mineralogist, A. S. Packard, jr., as entomologist, and C. B. Fuller 

 as marine zoologist. Others, including G. L. Vose and Dr. N. T. True, 

 rendered assistance at various times. 



Two brief seasons were devoted to Held work, the results of which 

 appeared in the reports of the board of agriculture for 18(31-62, the 

 strictly geological portions being limited to some six hundred and odd 

 pages. The work done under these conditions was necessarily some- 

 what disconnected. Northern Maine was still practically a wilderness; 



« The subject was in 1868 again taken up by Prof. G. L. Vose, whose conclusions, 

 based on a study of congiomerates in the vicinity of the Raugeley Lakes, were largely 

 confirmatory of those of the Hitehcocks. He was not, however, disposed to regard 

 the pebbles as having been in a plastic state, hut contended that under the forces 

 that had there prevailed rigid pebbles might be bent and flattened in the manner 

 described. 



Natural History 

 Survey of Maine, 

 1861-62. 



Fig. 73. — Charles Henry Hitchcock. 



