286 F. H. Bradley—Geological Map of the United States, 
. 
Both varieties are found at the Aguacates in veinlets, Some 
of these are filled with a conchoidal variety, like that from the _ 
Albert mine, while others consist of the same columnar and 
sub-conchoidal material as that from the Cristo mine. The con- 
choidal fracture in both differs simply as to degree, varying : 
with the degree of brittleness. _ 
A few barrels of the mineral from the Cristo mine havin | 
been sent last autumn to Glasgow, an analysis and technical 
examination of the sample were made by Mr. William Wallace, 4 
of that city. : 
ANALYSIS OF CRISTO-GRAHAMITE. a 
Specie pravity -o. FS eS 17156. : 
Illuminating gas... ..--61'3 a 
Volatile matter __._..._- har chs eee 46 > O2°1R 3 
Water. .cc. au a : a 
Fixed Carbon ..------- 31°63 
te tie et oe en | Sap A 
A io oe cg Bhai ale 
100°00 
ANALYSIS OF COKE. 
ROG ba as eu ce ide es de ee 83°56 
PURDUE ie oo on ps one coe cae ee a 
Art. XXXVI.—On a “ Geological Chart of the United States + 
of the Rocky Mountains, and of Canada ;” by FRANK 
BRADLEY. 
In publishing a new compilation of the gear ena 
geological surveys of the eastern United States and ep ne 
writer has felt under obligation to state the react 
adoption of any peculiar features of the chart, and also of data 
of noting some theoretical points to which this revision 
has called attention. + <chow mie ae 
: ue 
curately the general trends of the outcrops. The consed a 
: 
| 
: 
15°48 
10000 
| 
- . j i ple : 
distortion prevented the use of the ordinary mil ng the : 
