Maclure on Geology. 21 1 



evett in Edinburgh,* that focus of geological science. His 

 opinions on some of the more obscure and doubtful parts 

 of the Wernerian geology are worthy of peculiar considera- 

 tion ; for they are founded on a course of observations vastly 

 more extensive than Werner ever had it in his power to 

 make. The name of Werner will always be venerated as 

 long as geological science shall be cultivated, for geology 

 owes more to him than to any other man ; but his pupils 

 should not now demand that implicit and unqualified adoption 

 of ALL his opinions, which will allow no other question to be 

 raised, than what Werner taught or believed. 



With these explanatory remarks, the following extract o^ 

 Mr. Maclure's letter is now subjoined : 



DEAR SIR, 



Your letter of the 26th June came just as I was embark- 

 ing for Europe. The information it requires concerning the 

 primitive trap and flint slate, the transition and secondary 

 rocks, &c. &c. is difficult to give without the aid of specimens, 

 and frequently requires the examination of the relative posi- 

 tion of the strata before any correct idea can be formed. I 

 will, however, endeavour to give you the little my experience 

 has brought me acquainted with. 



Fbllowing the nomenclature of Werner, I have given a list 

 of his rocks ; but in describing them there are many of his 

 names which I do not use ; because I never met with them. 

 Primitive trap is one instance — 1 do not use trap as a substan- 

 tive, except in describing that kind of trap which Werner calls 

 the newest flaetz trap, the nearest to which is your trap,t 

 which covers the oldest red sandstone. 



The primitive flint slate is in the same predicament. I 

 have always found it on the borders of the transition, between 

 it and the secondary. 



Primitive gypsum 1 have not found. 



* Vide Edin. Review for Sept. 1818. p. 374.'' 



~ Referring to tht ridges of Greenstone near New-Haven. 



18* 



