Maclure on Geology. Qi 
becoming respect even in Edinburgh,* that focus of geological 
science. His opinions on some of the more obscure and doubt- 
ful parts of the Wernerian geology are worthy of peculiar con- 
sideration ; for they are founded ‘on a course of observations vast- 
ly more extensive than Werner ever had it in his power to make. 
The name of Werner will always be venerated as long as ge- 
ological science shall be cultivated, for geology owes more to 
him than to any other man; but his pupils should not now de- 
mand that implicit and unqualified adoption of azn his opin- 
ions, which will allow no other question to be raised, than what 
Werner taught or believed. 
With these explanatory remarks, the horas extract of Mr. 
Maclure’s letter is now subjoined: 
DEAR SIR, 
_. Your letter of the 26th June came just as 1 was embark- 
ing. for Europe.. The information it requires concerning the 
Primitive trap and flint slate, the transition and secondary rocks, 
Ke, &e. is difficult to give without the aid of specimens, and 
frequently requires the examination of the relative position of 
the strata before any correct idea can be formed. I will, how- 
ever, endeavor to give you the little my experience | has bee : 
me acquainted with. 
_ following the nomenclature of Werner, I have given a ~ ~ 
of his rocks; but in describing them there are many 
names phiel I do not use ; because I never met with the 247 
to which they refer. Primitive trap is one instance—I do not 
Us trap asa substantive, except in describing thet kind of trap 
which Werner calls the newest fleetz 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 Le psd 
the secondary. 
Primitive sypsum IT have not found. 
“Vide Edin. Review for Sept. 1818. p. 374. 
Referring to the Ridges of Greenstone near New-Haven. 
