Geology and Mineralogy. 259 



that of Maryland) while the Mediterranean Miocene finds a closer 

 analogue in the more tropical fauna of the Duplin beds of the 

 Carolinas." 



These volumes should be in the hands not only of stratigraphers 

 and paleontologists, but of all teachers of historical geology as 

 well, for here is given not only a detailed description of the 

 Maryland Miocene stratigraphy and its preserved organic remains, 

 but also the relationship of these faunas to those of other areas 

 of North America and of Europe. The State of Maryland is to 

 be congratulated on its able and active survey staff, under the 

 efficient leadership of Professor W. B. Clark. Among state sur- 

 veys it stands second, ranking next to that of the rich state of 

 New York. c. s. 



7. Palwontologia Universalis. — The third fasciculus of this 

 important republication of old or obscure species of fossil organ- 

 isms has arrived. These three parts treat of 15 species, figured, 

 and described in 161 sheets. This completes the first annual 

 subscription, which is eight dollars. The first fasciculus of the 

 second series will soon appear, and subscriptions should be sent 

 to G. E. Stechert and Co., 129-133 West 20th street, New York 

 City. The editorial work is in the hands of D.-P. (Ehlert, of 

 Laval, France, Secretary to the International Commission 

 appointed by the International Geological Congress, at its eighth 

 meeting. c. s. 



8. On the Melting Points of Minerals. — M. A. Brun has 

 recently published a second memoir on the subject of the fusion 

 of minerals, which was first discussed by him in 1902.* The 

 object of the present investigation has been to establish the melt- 

 ing point of the feldspars and some other important minerals 

 (leucite, chrysolite, wollastonite), both in the crystalline and 

 glassy states. The results now obtained are summarized by 

 the author as follows : 



"The present work will serve to control scientifically the values 

 previously given, and, also, to establish the melting points of the 

 colloids, which have the same percentage composition as the 

 crystals. 



The measures have been taken with the help of the calorimeter. 

 A large block of platinum was used as thermometer and Viole's 

 rule was used for the calculation of the temperature. 



The results of these experiments prove that the figures pub- 

 lished in 1 902 are exact. They therefore agree with the figures 

 given for the crystals. It is shown, moreover, that in the com- 

 plete thermic study of the silicates, the following points should 

 be determined. 



{a) The melting temperature of the crystal, (b) The melting 

 and softening temperature of the colloid (glass) which has the 

 same percentage composition, (c) The temperature needed to 

 bring about the crystallization of colloids, (d) The temperature 



* Arch, des Sc. phys. et nat. (4), xiii, April, 1902. See also the paper by 

 Day and Allen in the February number of this Journal. 



