102 Proceedings of the Association 
When the action was but slightly intermittent, a hexagonal 
plate might result with concentric striz. The strie of crystals 
have generally this intermittent origin, and with it is often con- 
nected a consentaneous intermittent action in the cause of sec- 
ondary planes, as alluded to on page 379 of the last volume of this 
Journal. The striz on the hexagonal compound plates of chry- 
soberyl are evidently of this character. The horizontal strize on 
some elongated prisms of quartz are of the same origin. And we 
remember no instance of strie that are not accounted for by the 
causes here presented. 
After astar has begun, its rays are sometimes terminated by 
hexagonal plates, showing that the variations of force alluded to 
may occur in the sam e crystal, according as it is exposed to dif- 
ferent external circumstances. Various other points might be 
touched upon ; but these are sufficient to illustrate the general 
a in view 
acts elucidate generally the mode of action in attraction, 
by whiel the relative length and breadth of an enlarging prism 
are determined 
The correspondence between these facts and the results of 
owth is too striking to be overlooked. The production of lat- 
eral branchlets to a branch of a plant at certain intervals from the 
with the character of the crystals alluded.to. This point is dwelt 
upon by the author in his work on Zoophytes.* We thus see 
that both vital and physical forces operate according to a ~— 
general law, and the fullest demonstration is before us of the 
unity of plan throughout created existence. 
Art. XVI.—Proceedings of the Meeting of the Association of 
merican Geologists and Naturalists, held at Boston, Se, 
tember, 1847.+ 
1. Notice of five new se of Fossil Mammalia from Iie 
nois ; by Joun L. LeConte, M.D.—The fossils which form the 
subject of the following ities were found in the lead region of 
Illinois, by Mr. Wim. Snyder of Galena, by whom, with the ut- 
most liberality, they were presented to the author. The exact. 
geological period to which they belong is not known, as they 
were not found in sifu, but in a crevice fifty feet below the sur~ 
face; this crevice was filled with a mixture of clay an 
by oxyd of iron, into a hard mass, which cannot be en- 
pon yeihaved without great injury to the specimens. 
hytes, 4to, pp. 85-100. sgh? 
tracts, excepting the one on heat, have eee furnished by. the 
i 
OS” Soc a a eels 
