198 TZ. B. Brooks—Rocks observed in the Huronian Series. 
(16.) Syenytic Gneiss (Hornblende Gneiss). (L.)—z7. 
abundant; rare in the Marquette pe: egion, where it oa ae 
as a transition ‘assety of greenston 
(2.) Hyposyenyte (quartzless ayenvand Observed only in the 
Lower Huronian near Marquette, associated with greenstone, — 
into which it seems to graduate. Rich in orthoclase—é, — 
Hornblendic—77. 
(26.) Zircon-syenyte. 
3.) Dioryte—75, 118. Grayish-green, fine to coarse grained. 
Abundant, eapecially in the eastern part of the Marquette Re 
gion, graduating into homilies rocks on the one hand, and, 
through schistose varieties and diabases (?), into chloritic schists 
on the —_ Hornblendie. Chloritic (schistose)—71? Semi 
rphy1 
2 ) Gab Gabbro* ?—69. Confined to bed XV, in the Menominee 
Regi 
4. = ersthenyte. 
i) Diabisayle + AGasauie especially south of L: Aner This 
name is often applied by Dr. Wichmann to obscure, in 
greenstones which have usually beet called diorytes, di 
schists and chloritic diorytes. Decompos fe 
Often closely related to one variety of chlorite hat cons 
Green, related to dioryte—72, 119, 69. Black, somew | 
grained, highly crystalline, distinct from the other 
—§2. Porphyritic?—83. Micaceous?—3l. n black, coun 
(6.) Hornblende Schist. (L.) Abundant. Greenis te 
grained, semi-schistose to massive, graduating ee sociated 
—18, 22, 30, 88. Eminently schistose, eee Chloriti 
with mica schist—128, 725. Micaceous—29, £27, 
—76. Ca leareous—r2¢ , rare 
(7.) Be oremoiegs (L. 196. Far less abundant tay a 
(8.) a ee Chiefly confined to t | 
Region. Not abun dant in the Mar 
Anthophyllite Sahieth ‘Brush) Quite abunda eau a 
quette and Menominee Regions, and always assoc! 30, Garnet 
magnetite. Manganiferous—s@, 59. Qu artzose—180 es 
iferous (eklogyte)—27.§ eo 
* Dana does not mention gabbro among gece al a the ae aes : 
ae 
eis eS ee SH beats Saees —ar e a 
ice Se 
lithologists agree on the name, and the bed 
istios of the others of this series, I place it here 
the rock rTornebobme, Wit 
+ From microscopic researches, Dr. Wichmann 2 ine rae yies nd ce 
Prof. zack agrees, regard these Huro eo nas 
as ytes, and consider aed of oraptite 5 wa in Jet 
myself as metamorpbo, I should he have employed ge “2 tose 
suggested by Prof. Dan: e to my 
This cannes 
ne 
Dr. Wichmann’s microscopic examinations 
made up largely of actinolite te dated July 27. 
