9o2—CO Geological and Mineralogical Notices. 
we have a. 68°, b. 112°=180°; ¢, 108°, d. 72°=180°; from 
which was constructed the annexed figure. ‘These measurements 
Rhomboidal Limestone. 
7 feet long, 5 wide, 1 thick. 
were repeated on the same stone, and on different tonal, and the 
angles opposite to them were also measured, and found to vary in no 
important manner, indicating a very remarkable regularity and paral- 
lelism of the opposite sides. Running across the stones in two di- 
rections, parallel to the sides, were distinct superficial cracks, and 
vage through them would cut the mass into many precisely simi- 
lar solids ; showing clearly, that the same cause that produced the 
main fissures, now by the running water, enlarged to inches in width, 
completely impressed its force and conferred a similar structure upo! 
the whole. The dimensions of these rocks are very various, as may 
be seen by the measurement of some—ft.1xX1X6. 5x7X1— 
figured above, 46X24. This last, with the specific gravity of 
2.5, must weigh 37$ tons. 
The attention now paid to the structure of rocks by such observers 
as Conybeare, Sedgwick, De la Beche, and others, assures us of the 
importance of treasuring up every fact, and in its description de- 
ing to minute particulars, how little soever we may at present 
be able to appreciate them. I regret therefore that my time having 
been mostly devoted to the collection of minerals on that day, pre- 
vented definite observations on some collateral points of importance, 
as the dip, direction, &c. of the strata—though my impression is 
they varied little from a horizontal position. 
hares oe has excited new interest, and received new light from 
- Hopkins’ researches, reported to the late meeting of the British 
ion, . aod: the ye ey snc’ seem already to 
* 
promise the The remark 
of Mr. Phillips that ‘es a i the structure (in the arena- 
ceous, argillaceous, and calcareous rocks) increased with the anti- 
a 
