478 Scientific Intelligence. 
e Dimetian, Arvonian and Pebidian formations. — 
These subdivisions of the Pre-Cambrian, proopsed by Dr. Hicks 
from his observations at St. David’s, on the ground of mutual 
intersecting the Cambrian; and the Arvonian, eruptive quartz- 
porphyries or elvans associated with the granite—proof of which 
was found in natural oe ns showing the actual intrusion of the 
ne across the be of the rocks. 
On the results of Recent explorations of erect trees contain- 
te yp tact remains in the Coal Formation oS Nova Scotia ; 
by J. W. Dawsoy.—Part II- of Dr. Dawson’s memoir is pub- 
lished in the Philosophical Transactions for 1882 
13. Lethea Geologica; etl, Lethoa Paleozoica, von Frerp. 
Roemer. Textband, ae Lieferung. 327-544 pp., with 65 
wood-cuts. 8vo. Stuttgart, 1883. (E. hat tip a As —This part 
Ls 
of the Lethza, by Roemer, is devoted wholl ossil Corals, and 
wil ound of great service to ra pa paleontologists 
He or yte . Dan n the writer’s paper “on 
spores mica as a characteristic ingredient under the same coacnal 
name with those that are essentially hornblendic. Accordian 
in my articles on the Cortland rocks in this Journal for 1880 on 
page 198 of volume xx, I called a rock of the kind here referred 
to simply a hog Shopng in allusion to its resembling granite in 
aspect and in being a compound of feldspar and mica, with more 
or less quartz, and to its containing a cae lime feldspar, oligo- 
clase, instead of orthoclase. 
As it is best that the rock should have a distinctive name I 
would propose for it that of Hemidioryte, which recognizes its 
relation to dioryte, without merging it in the Bacpl An group. 
15. ee anew mineral—M. Damour has recently de- 
scribe a w borate of alumina from Siberia under the name 
eae and ye in habit, Harton 6°5, specific eae 28, 
analysis yie ed: 
