NEW HAMPSHIRE. 



397 



tin com form ably This theory will explain the occurrence of the whet- 

 stone rock in limited outlying patches Were it intcrstratified with the 



hornblende, it should descend into the earth at the same angle to indefinite 

 depths." (Geol. of New Hampshire, II. , p. 379.) 



On examination, however, of this so-called hornblende schist, both in 

 the hand specimen and microscopic slide, we find it to be a well-marked 

 diabase, a rock that so far has always, when carefully studied by com- 

 petent observers, been considered to be eruptive. 



No. 121, called '-granite from bed "in the Preliminary Catalogue, 

 (''feldspar from bed," Hawes's Catalogue) is the same as the sandstone 

 No. 117 (Prelim. Cat.), both being masses of feldspar with a little quartz. 

 No. 86 of the Preliminary Catalogue, called " serpentine, very impure," 

 from Norwich, Vt., is regarded as Huronian. (Geol. of New Hamp- 

 shire, II., pp. 3G0, 361.) This rock is a mixture of quartz and horn- 

 blende, with considerable epidote, but we cannot find the slightest sip-n 

 of serpentine about it, either inacroscopically or microscopically. 



We might go much further in illustrating the character of the litho- 

 logical determinations of the New Hampshire Survey, and the probable 

 value' of these as forming a basis for a geological classification, but we 

 forbear. 



The criticisms here made depend of course on the -authenticity of the 

 specimens used. On this point We quote Prof. Hitchcoc^v : — 



"Pains have been taken to hxave all the specimens exactly alike, so that 

 those wjio obtain duplicate collections, by purchase or otherwise, may be sure 

 that Mr. Hawes's accurate descriptions in the chapter on Lithok^gy are appli- 

 cable to their set." (Geol. New Hampshire, Part IV. p. 261.) 



Dr. Hawes, however, appears to have had his doubts with regard to 

 the uniform character of the various collections p?-epared by the New 

 Hampshire Survey, for he expressly states that it is only for the collec- 

 tions preserved in the Pcabody Museum at Yale College that he is to be 

 held responsible [L c, p. 255).* 



Further remarks on the methods of work of the New Hampshire Sur- 

 vey, and the character of the classification established on a purely 

 lithological basis, will be found in the second part of this memoir. At 

 present it will be sufficient to present iu a tabular form (Table B.) the 

 difFerf^nf rpsnlts arrived at from year to year, as displayed in the re- 



* It is a fact, as shown by actual examination^ that, in various collections obtained 

 from Prof. Hitchcock by diircrcnt parties,--Bpecimons bearing the same number, and 

 purporting to he from the same locality, are ~ in some cases, at least -~ quite differ- 

 ent from each other. 



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