532 
in New Jersey and skirting the Mississippi below the junction of the 
Ohio, are the principal materials of importance which have subse- 
quently been added to his spirited and_ masterly original sketch. 
His introductory remarks show that he was equally well acquainted 
with the general outline of the geology of Europe. 
He declines entering on the subject of organic remains, not. as 
unaware of its importance, but because they “‘ had not yet been ex- 
amined.” In his preface occur some remarks which may show how 
unjustly the earlier geologists have been charged with too great in- 
clination to depart from the ordinary laws of nature : “In all specu- 
lations on the origin, or agents, which have produced the changes 
on this globe, we ought,” he says, ‘to keep within the boundaries 
of the probable effects resulting from the regular operations of 
the great laws of nature, which our experience or observation have 
brought within the sphere of our knowledge.” It is remarkable 
that Mr. Maclure mentions galvanism as an agent which may have 
co-operated in changing and metallizing rocks: “A galvanic pile,” 
he says, “ may be formed in the stratifications of a mountain, as - 
well as in a chemist’s laboratory.” 
His treatise ends with two chapters on the probable effects of the 
decomposition of different classes of rocks on the nature and ferti- 
lity of soils; being an attempt to apply geology to agriculture. He 
is the father of American, much more than Smith is of English, 
geology ; and American geology is especially important, because in 
America and in Russia we have two of the largest classes of forma- 
tions, the Silurian and Carboniferous, developed at the distance of 
half an hemisphere. We may, with good cause, congratulate our- 
selves that this comparison will shortly be consummated by the 
distinguished author of the ‘ Silurian System,’ whom we have this day 
elected to be our President for the ensuing year. 
In 1822 Mr. Maclure published some speculative conjectures on 
the probable changes that may have taken place in the geology of 
the Continent of North America east of the Stony Mountains (Sil- 
liman’s Journal, vol. vi. p. 98), in which he considers that a very 
extensive lacustrine condition of the upper country prevailed before 
these waters were discharged by the gorges that give exit to the 
present great rivers, and observes, that “the large masses of granite, 
some of them weighing tons, which are scattered over the second- 
ary strata between Lake Erie and the Ohio, while there is not an 
atom of granite in place nearer than the north side of the Lake, 
would seem to point at the only mode by which they could probably 
be transported—viz. by supposing the Lake extended thus far, and 
that large pieces of floating ice from the north side might have car- 
ried those blocks with them, and dropped them as the ice melted 
in going south; the fact of few or no blocks being found south of 
the Ohio, shows that the southern sun melted the ice before it got 
so far. (Silliman’s Journal, 1893, vol. vi. p. 102.) 
It must be no less gratifying to the family of Mr. Maclure than 
it is to the great scientific family of the investigators of nature 
throughout the world, to learn that the Academy of Natural Sci- 
