428 
POPULAR SCIENCE REVIEW. 
tion, or by the combination of acetylene with nitrogen, also in equal volumes 
without condensation, 
C 2 N + H = C 2 NH; C 2 H + N = C 2 HN, 
points to a striking relation between these two bodies, regarded as compound 
radicals. — ( Compt . rend., 1879, lxxxix. 63.) 
GEOLOGY AND PALAEONTOLOGY. 
American Jurassic Mammals . — Professor O. C. Marsh has discovered some 
interesting remains of small mammals of Jurassic age, in the so-called 
“ Atlantosaurus beds ” of the Rocky Mountains. All the specimens are 
lower jaws, as is general in our own Stonesfield and Purbeck deposits, and 
they have enabled their discoverer to distinguish four species. Two of these 
he regards as Marsupials, but as belonging to a peculiar genus, Dryolestes. 
One specimen possesses the strongly inflected angle characteristic of marsu- 
pial mammals ; another shows that the number of premolar teeth was at 
least four, showing that the genus is quite distinct from Didelphys. Pro- 
fessor Marsh names the species, both of which were of small size, Dryolestes 
priscus and D. vorax. A third species is represented by the left side of a 
jaw, the two extremities of which are either wanting or badly preserved. 
It is remarkable for the great number of molar and premolar teeth, which 
are apparently at least twelve in number, and possibly more. Some of the 
premolars have two fangs ; all the molars are single-fanged ; the former have 
compressed and recurved, and the latter conical crowns. A large pointed 
tooth lying near the jaw is regarded as probably a canine. The animal, 
which was somewhat smaller than a weasel, and probably insectivorous in 
habits, presents close resemblances to the genus Stylodon of Owen, from 
the English Purbecks, with which Professor Marsh thinks it may constitute 
a distinct family, Stylodontidse. He names it Stylacodon gracilis, the specific 
name being in allusion to the slenderness of the jaw. A fourth form is said 
to resemble in some respects the genus Triconodon of Owen, the molar teeth 
having each three pointed cones ; but there are four such teeth instead of 
three, and the middle cone in each tooth is larger than the others. The 
angle of the jaw is much produced but not inflected ; the author neverthe- 
less regards the little animal as having been probably an insectivorous 
Marsupial, allied to Triconodon and Phascolotherium. He names it Tinodon 
bellus, and suggests that the uninflected angle of the jaw, and the position 
of the coronoid process, which ascends at right angles to the ramus imme- 
diately behind the last molar, would indicate that it forms the type of a 
new family (Tinodontidse), if not that it may have been a placental mammal. 
— ( Silliman's Journal, July and September, 1879.) 
Deli's Hair. — Professor Dana publishes some notes on the curious fibrous 
product of the crater of Kilauea, commonly known by the above name, 
founded on a supposition of the natives that it was the hair of their goddess 
Pel6. Professor Dana gives two new analyses of this substance, which are 
very nearly accordant. Their mean shows a composition almost precisely that 
of ordinary dolerite, as shown in the following comparative statements : — 
