Geology and Mineralogy. 65 
4, Probabie pion — of the Great Salt Lake,—It is be- 
lieved that the explorations of the survey under the direction of 
r. Hayden, the past satan have determined the probable an- 
cient outlet of the great lake that once filled the Salt ‘ake Basin. 
t the head of Marsh Creek, which occupies the valley, continu- 
ing directly south from that of the lowest Portneuf, is the lowest 
pass between the Great Basin and the drainage of the Columbia. 
In fact so low and flat is it, that a marsh directly connects the 
two streams, one flowing to the Bear River and the other to the 
Portneuf and Snake Rivers. 
This fact was observed by the Survey in 1871 and 1872, but 
this district has been carefully examined the past season by Mr. 
oe and Dr. 
Siberian Steppes. —Professor John Milne, in a paper enti- 
tled “Across Europe and Asia, Part V, from Ekaterinburg to 
Tomsk” (Geol. Mag., ages ree ar suggests that the material of ~~ 
ted b 
great — of Siberia y the rivers while t 
were r floods paused oy Abi being dammed about hae 
shouths 3 in eekaeaaides of the ice of the stream not having there 
melted. He shows that although ae — of — of the wa- 
ters in autumn differs but a week o in the more northern and 
asiot heat parts of the rivers, the Gies of saclline i in the spring often 
Iife nth Consequently the ice toward the mouth of the 
their norther were 
neath the sea—more or less constantly coin alah a lake of tur- 
bid water.” Floods ra this source occur now in Siberia. This 
One, plain accompanies it; and as it expands in flowin 
northward, so with the plai The widening “ se plains con- 
= until they unite to — that ge aa which 
a Mikroskopiache Piysiographie de pases Gesteine, von 
Rosenpuscu. 6 pp. 8vo. Stuttgart, 1877. (E. Schweiger- 
~ sche Verlagshandlng. apna presen t work forms ane operly a 
Am. Jour. S8cl.—Tuirp Serres, Vou. XV, No. Se 
5 
