398 A, A. Julien—Cymatolite from Goshen, Mass. 
The granites which Major Brooks places in his scheme as 
the youngest of the Penokee Huronian (see this Journal for 
September, 1876) are merely intrusive patches and veins of 
small size and area, cutting both the upper mica schists of the 
Huronian, and the Jower gabbros of the Keweenawan system. 
The gabbros are placed unhesitatingly with the Keweenawan, 
for the following principal reasons: (1) their general mineral 
composition allies them closely with the typical diabases of the 
Keweenaw series while contrasting them with the hornblendic 
Huronian; (2) when followed along the general trend of the 
formation, they are found giving place to typical Keweenawan - 
diabase and diabase amygdaloid; (8) similar gabbro occurs 
interstratified with the undoubted Keweenawan rocks; (4) the 
gabbro belt cuts diagonally across the Huronian, which it nar- 
rows in places to less than one-third the full thickness, thus 
proving a distinct non-conformity. These gabbros are regarded 
as of igneous origin, having been one of the first of the great 
flows of the Keweenaw system, and laid down upon the slightly 
disturbed Huronian beds. 
University of Wisconsin, Dec. 31st, 1878. 
Art. L.—On the Composition of the Cymatolite from Goshen, 
Mass. ; by A. A. JULIEN. 
A MINERAL, pseudomorphous after spodumene, occurs in 
granite veins of Hampshire County, Mass., which appears to 
be that first found by Shepard, and by him called cymatolite. 
The variety at Goshen was analyzed by Barton, and, on the 
ground of his results, has been assigned to pihlite. A specimen, 
identical in physical characters with the mineral of Shepard, 
has yielded me the following composition : 
Oxygen. 
W htere crs 4s ees ae 2°29 
Nitrogenous organic matter.... °43 
TT OPOBN e 1°42 
MM woe toe ee 2°57 66 
SS ee eee eee 05 
es ee “48 14 
M ee Pa ananet ens “75 *30 
Manganous See... ce 04 
Ferric oxide .__.__- 22 ee 49 
Ga a ee 24°38 11°38 
Senta oe ee ee Be TI 30°99 
99°61 
These new results, corresponding by the old system to the 
(4(@H+43K . Na)’+§3aAl)sr’, 
