BS ee 
Mineralogy and Geology. 277 
the animal, this involves a much greater difficulty ; for so delicate a 
structure would have been dissolved by the gastric juice, and could not 
have reached its present position. 
The Rev. Dr. Buckland and Prof. Owen, who have kindly written 
me on the subject, state, that there is no reason why the ichthyosaurus 
should not be viviparous, although “analogy of the nearest existing 
reptiles would point to its oviparity as the more probable kind of gene- 
ration; but the genus Zootoca and the Viper show that analogy is no 
safe guide in such a question ;” “ and the European black and yellow 
salamander of Bohemia once brought forth young ones half as long as the 
smother, either in the doctor’s pocket or college rooms;” therefore 
with such evidence it now appears fair to conclude that the ne mme 
were viviparous. 
19. Grooves or Scratches in North Wales; by A. F. Mactnrosu, 
(Quart. Jour. Geol. Soc., No. 4, 1845, p. 460.)—Mr. Macintosh, after 
describing many instances of the fluting or striations of rocks in North 
Wales, proceeds to show that they cannot be explained by the hypo- 
thesis of icebergs, and must be attributed to peculiarity of structure in 
the rocks. In a case near Bedd Gelert, he remarks that the flutings 
are more regular, more accurately parallel and more symmetrically 
placed, than could be the case had they been produced by the passage 
of a glacier. There is scarcely any variation in depth or direction, and 
however numerous the lines, they are uniformly and strictly parallel. 
Phenomena of such a kind he concludes must be structural. Similar 
evidence in other regions is appealed to in support of this conclusion. 
Certain low rounded rocks in the valley of Llugwy are regularly fur- 
rowed in continuous parallel lines, not only from top to bottom, but on 
the sides accessible to view. Certain conglomerates have broader and 
wider flutings: than the schists; and moreover, fragments of schist in 
these conglomerates have fine flutings wholly independent of the rock 
containing the fragments. Mr. Macintosh maintains farther that there 
is a connection between the flutings and the cleavage, the former being 
parallel with the latter. He suggests that the striated and furrowed 
rocks in the United States, attributed by Prof. Hitchcock to glacial 
action or ice, may be of structural origin. 
20. Phosphorite Rock of Estremadura, Spain, a good siatenial for 
manure, (Rep. Brit. Assoc. for 1844, p. 28.)—Prof. Daubeny states that 
this rock forms a solitary mass, penetrating clay-slate, the dimensions 
being at most fourteen feet in width, its length along the surface of the 
ground extending to about two miles. The composition is about 80 
per cent. of triphosphate of lime and about 14 fluoride of calcium; 
and he suggests as a final cause of the secretion of so large a mass of 
both these substances in the older rocks, their being intended to supply 
