722 General Notes. _ [Augtist, 
has collected fossils which are of triassic age; while the plants of 
the coal-basin of Hone-Gay have been referred to the Rhetian 
period. According to these observations the Trias is, in the in- 
terior, superposed upon ‘the Carboniferous, while the coast 
coal-measures of infra-Liassic age rest directly upon the carbonif- 
erous limestone in one of its folds. The actual coal-beds do not 
appear to extend beyond Dong-Trieu, but the strata are more 
extensive, and it is not unlikely that detached portions of coal 
-may be found among the hills of arkoses which rise out of the 
rice-fields of the Delta. The beds of coal are thick upon the 
level of the soil, very little above the sea, and near to it, but the 
quality of the combustible is inferior. 
Cretaceous—Paul Pelseneer (Bull. du Mus. Roy. d’ Hist. Nat. 
de Belgique) describes certain remains of a macrurous crustacean 
found in the green sand of Grandpré, in the Ardennes. From 
_ the sum of its characters it is clearly an Astacomorph, and the 
form of its rostrum (without lateral spines) places it in the genus 
= Hoplopariz., The new species is named H. benedeni. Compari- 
i: son of Hoploparia with Homarus and Nephrops induces M. Pel- 
Sencer to consider it nearly related to the former genus. : 
seventh more advanced medial horn. The tail is long and stiff, 
its vertebræ encased in an osseous sheath developing tuberous 
’ 
MINERALOGY AND PETROGRAPHY-.' 
PETROGRAPHICAL News.—In the June number of the Geologica — 
agazine Professor Judd has an interesting article? in which he . 
ats of the structure and origin of the little glassy balls known . 
as Marekanite, from their occurrence—the great Marekanka, ans 2 
khe , in Siberia. A résumé is given of the work previousty 
1e on the subject and some additional observations are recore™ ~ 
According to Judd the internal structure of marekanite balls ia- 
fers from that of Prince Rupert’s drops in that they contain vo® 
tile ingredients in such quantity that when heated the entire gp 
Edited by W. S. BAYLEY, Johns Hopkins University, Baltimore Md, 
tarekanite and its Allies, p. 241, 
i 
