402 The American Geologist. Tune, 1892 
ena are especially valuable. Several of the maps, based largely on. 
explorations by the Moravian missionaries, have been drafted for this. 
work and are superior to any previously published. 
Exploration on Grand River, Labrador. By Austin Cary. (Bulletin,,. 
Am. Geog. Soc., Vol. xxiv, pp. 1-17, with a map; March 31, 1892). The 
Bowdoin College expedition in 1891 to the falls of the Grand river in. 
Labrador, of which a brief narrative is given in an appendix of Prof. 
Packard’s volume, is here more fully reported. The largest fjord of 
Labrador, about 150 miles long, known as Hamilton Inlet, terminating in 
lake Melville, receives at its head the Grand river. The distance along 
the river from its mouth to the falls is nearly 300 miles. For nine miles. 
next below the falls the river runs in a narrow postglacial canon, 300 feet 
deep close to the falls and 800 to 1,000 feet deep at its lower end, where 
it opens, like the gorge below the falls of St. Anthony on the Mississippi, 
into a wide preglacial valley, whose upper part is occupied by a compar- 
atively small tributary. The canon is eroded in the hardest crystalline 
rocks, which form a plateau in that region about 2,000 feet above the sea; 
and the amount of its erosion, as of the gorges below Niagara and the 
falls of St. Anthony, affords a measure of the length of postglacial time. 
The vertical fall, probably due to systems of joints in the rocks, was esti- 
mated by Mr. Cary to be somewhat less than 200 feet, but has since been 
more reliably d+termined to be about 300 feet. Strong rapids extend 
several miles both below and above the falls. 
On the Osteology of Mesohippus and Leptomeryx, with Observations on the 
Modes and Factors of Evolution in the Mammalia. By W. B Seorr. (Jour- 
nal of Merphology, Vol. v, No. 3, pp. 104, with two double plates and 
nine figures in text). 
This is a worthy sequel to the admirable memoir on Pewbrotherium by the 
same author, briefly noticed in the November number of the GEOLOGIST. 
The first 41 pages are occupied with a study of Mesohippus in its rela- 
tions to existing equine forms. 
The typical species of this genus WM. bairdii, first referred by Leidy, 
its describer, to the genus Palwothertum and later to Anchitherium, has 
usually been referred to the latter genus, but, as has been shown by 
Scott*, belongs, by the non-invaginate enamel of its incisor teeth, to an- 
other genus, for which he has retained the name, Mesohippus. The genus 
Mesohippus, originally proposed by Marsh on characters which, so far as 
different from those of Anchitherium, are of merely specific value, is thus 
saved /iterully “by the skin of its teeth.” 
Of the two genera, Anchitherium and Mesohippus, the latter is regarded. 
as the more primitive form, and it is questioned whether the former 
genus be in the line of equine descent and whether it do not rather form. 
a side branch. 
After a detailed description of the parts of the skeleton, a full-page- 
restoration is given, in connection with which Prof. Scott remarks: “The 
successive genera of the horse species show for the most part a steady 
Science. Vol. ym. 
