73 
and usually occurs as well defined, wedge-shaped crystals, 
often of considerable size. 
In the accompanying table analyses are given of the 
normal essexite which forms the greater part of Mount 
Johnson, and of the finer grained, olivine-bearing variety 
of the same rock found at the summit of the mountain. 
For purposes of comparison there is presented in the same 
table the analysis of the essexite from Shefford mountain, 
which belongs to the same Monteregian province, together 
with analyses of the original essexite from Salem, Mass., 
and of allied rocks from two other localities. A partial 
analysis of the transitional rock between the _ essexite 
and the pulaskite of Mount Johnson is also given. The 
analysis of the Mount Johnson essexite (No. I) as well as 
for that of the associated pulaskite, which is given below, 
was made by Professor Norton-Evans, while the analysis 
of the olivine-bearing variety of the essexite (No. II) was 
made by Mr. M. F. Connor. 
Ip JUS Ill. We V. Vi. 
Soe be eee 48-85 48-69 53°15 46-99 47°67 50:40 
PO 2. 3... 2°47 2-71 1-52 PISO D ee eae. I-17 
Os... 19°38 17°91 17°64 17°94 1352/24 ok ee eee 
FeOs.....<. 4-29 3:09 3-10 2-56 oe 5-58 
ee ae: -- 4°94 6-41 4°65 7°56 3°85 
NiO0+CoO not det O05) not det.) notdet.|... ee) not det. 
i 0-19 0-15 0-46 trace. 0-28 0-77 
MgO.. 2-00 3-06 2-94 222 OS3I5 eh: 
CAO sss 7-98 7-30 5:66 7°85 8-03 6-77 
Bae ..:.. : 0-08 0-13 MONE: |e i lees ee 
INO ee. 2 5°44 5°95 5-00 6°35 4°93 6-24 
3 eae I-QI 2-56 3-10 2-62 2°97 2-56 
| 541 0 Foe ear ees 1-23 I-11 0-65 OROA lie, mur ee. 0-09 
(Oe ee not det.| not det OuOFAE Sea oe bea ea eas eee 
MO) ee en 0-68 0-95 I-10 0:65 B X82) avamernnts 
Bota. =. 99:36} 100-02 99°84} 99:60} 100-15 
I.—Normal essexite (andose), Mount Johnson, Quebec. 
I].—Olivine-bearing essexite (essexose), Mount Johnson, Quebec. 
IlI.—Essexite (akerose), Shefford mountain, Quebec, (American 
Geologist, 1901, p. 201), (with CO2 0-39 and SO: 0-28). 
IV.—Essexite (essexose), Salem Neck, Salem, Mass. (Washington, 
Jour. Geol., 1899, p. 57). 
V.—Theralite, Elbow creek, Crazy mountains, Montana. 
VI.—Rock forming transition from essexite to pulaskite, Mount 
ae Quebec. (Partial analysis. The iron present is all calculated 
as FeO. 
