Mineralogy and Petrography. 347 
of the new genus Tetrastylus ; two each of Morenia and Orthomys ; 
Myopotamus paranensis; Plexocherus paranensis, previously de- 
scribed as a Hydrocheerus, but differing from that genus in the struc- 
ture of the last molar; two forms of the new genus Cardiatherium, 
etc., ete. Many already known species and genera—such as Toxo- 
don, Paradoxomys, etc.—receive additional elucidation in this text. 
Macrauchenia bravardi and M. rothii are separated, under the 
generic name of Scalabrinitherium ; while Oxyodontherium zeballosi 
is equivalent to the M. minuta of Burmeister. Promegatherium 
remalsumis, a sloth-like animal, nearly as large as Megatherium 
americanum ; and Pseudolestodon equalis is another huge sloth. 
omaphoras concisus and Proéwphractus limpidus are among the new 
loricate edentates. Remains of Cetacea are abundant in marine 
which overlie the fresh-water strata. 
PLEISTOCENE.—Dr. Alfredo Dugès describes ina recent num- 
ber of La Naturaleza a Pleistocene fossil, which he names Platy- 
gonus alemanii. The skeleton appeared to be complete, but was in 
gent part destroyed during the excavation. The animal was almost 
ouble the size of the modern peccary. 
MINERALOGY AND PETROGRAPHY.'* 
PETROGRAP L News.—The very interesting paper by Brauno? 
on the palæopicrite of Amelose, near Biedenkopf in Hessen Nassau, 
contains a full description of this rock and its numerous alterative 
products. The freshest type of the palæopicrite is composed of 
idiomorphic olivine, augite, both idiomorphic and allotriomorphic, 
irregular grains of plagioclose, picotite and magnetite. The augite 
often shows the unusual alteration into biotite. The principal alter- 
ation products of the rock are serpentine, siliciophite, chrysolite, 
metaxite, picrolite, webskyite,’ calcite and quartz. The three sub- 
stances chrysolite, metaxite and picrolite are studied in great detail, 
and their optical and physical properties are described at length. 
The author regards them each as a variety of serpentine, the first 
consisting of slender elastic fibres, the second of coarse stiff needles, 
and the third being characterized by a radiating structure. 
The serpentines, amphibolites and eclogites from the neighbor- 
hood of Marienbad, in Bohemia, were formerly regarded as sedi- 
mentary beds which had been metamorphosed by the action of 
granite, which occurs near them ina boss. Patton has recently 
examined these rocks very carefully. He considers‘ them as prob- 
, Edited by Dr. ; rville, Maine. 
s Neu oa Joke Cue 2 Ue pt md Wate 
‘ gegen Naturalist, Nov., 1887, p. 1021. 
» u. Petrog. Mitth., 1887, ix., p. 89. 
