7> Scientific Intelligence. 



those which are euteotic and those representing the component in 

 excess. When crystallized they furnish anchi (nearly) euteotic 

 rocks and anohimono-mineralic rocks. This is purely hypothesis, 

 and for this reason and because the rocks which represent the 

 entire magma are not considered. Cross dismisses magmatic classi- 

 fication by eutectios as fundamentally weak and practically inap- 

 plicable. In considering the factor of mineral composition as 

 applied to classification, he concludes that the distinction bet ween 

 feldspathic and non-feldspathic rocks, which has been so sharply 

 drawn in the past, is unnatural, and entirely arbitrary. The use 

 of texture, in which correlations of specific kinds with geologic 

 modes of occurrence are made, he considers to be based on long 

 disproved generalizations made from limited observations. i 



He then takes up the quantitative system and replies to vari- 

 ous criticisms which have been made upon it, showing in many 

 instances that these have been based on misapprehensions. The 

 reply is especially directed to refuting the strictures of Harker. 

 In conclusion he questions whether any system of classification 

 can be strictly natural, because all the important characters of 

 igneous rocks are gradational. A logical classification must be 

 based on the quantitative development of fundamental characters, 

 and divisions must be based on artificial boundaries, since natural 

 ones do not exist. This brings us logically to the Quantitative 

 System. 



The reader will find this an admirable statement and a critical 

 discussion of present views regarding the subject of classification 

 of igneous rocks. It should be carefully read and considered by 

 all petrographers. l. v. p. 



III. Botany. 



1. A Botanical Survey of the Galapagos Islands; by 

 Alban Stewart. Proceedings of the California Academy of 

 Sciences, Fourth Series, Volume I, pp. 9-288, 19 plates, 1911. — On 

 account of their isolated position the Galapagos Islands are of 

 special interest to students of plant geography. The present 

 important contribution to their flora is largely based on the per- 

 sonal collections and observations made by the author while bot- 

 anist to the Expedition of the California Academy of Sciences, 

 during the years 1905 and 1906. Since the expedition lasted for 

 over a year, a thorough exploration of the islands was made pos- 

 sible. Mr. Stewart first gives a complete list of the vascular 

 plants known from the islands, following the treatment pursued 

 by Professor B. L. Robinson in his "Flora of the Galapagos Isl- 

 ands" of 1902. The list, which makes up the bulk of the paper, 

 includes numerous species reported for the first time, ten of which 

 are described as new. He then discusses, among other topics, the 

 botanical regions of the islands, the general features of the flora, 

 and the origin of the flora. A very useful bibliography of the bot- 

 any of the Galapagos Islands, compiled by Miss M. A. Day, is 

 given at the close of the paper. a. w. e. 



