160 Scientific Intelligence. 



that widely known by the name of Magnet Cove, where there is 

 an extensive development of rocks of the elaaolite-syenite type 

 and with them certain remarkable leucititic dike rocks of very 

 high interest. These contain large crystals, sometimes nearly an 

 inch across, of pseudoleucite crystals now entirely altered to a 

 mixture of orthoclase and eloeolite, also ekeolite, orthoclase, 

 jegirite, pyroxene, biotite, etc. The author discusses these rare 

 types of rocks with great fulness and also the various contact 

 rocks and contact minerals of the whole region. The latter in- 

 clude those of the quartz and sandstone, as brookite, rutile, etc., 

 also those of the calcite, including perofskite, vesuvianite, monti- 

 cellite and others. 



This volume of Dr. Williams is a model of careful, thorough 

 work, honorable alike to the author and to the State, and its 

 varied contents have been hardly more than hinted at in this 

 notice. It gains an additional and melancholy interest from 

 the fact that it was the chief and last work of its. lamented 

 author, who did not live to see it in complete form ; it is stated 

 that the disease which so abruptly closed his labors was contracted 

 during the work in the field which is here recorded. 



III. Botany and Zoology. 



1. On specific Assimilation in TImbelliferm. — M. Geneatt de 

 Lamarliere (Comptes rendus, July 27th, 1891), recounts the re- 

 sults of interesting experiments on leaves, conducted in the 

 Biological Laboratory at Fontainbleau, under the direction of 

 M. Gaston Bonnier. The Order Umbelliferm presents good mate- 

 rial for the comparison of the amount of assimilation in different 

 leaves of the same area. The activity of assimilation in dissected 

 leaves is appreciably greater than from the same surface of leaf 

 in a single segment. This difference is uniformly correlated with 

 the minute structure: dissected leaves in this order have two or 

 more layers of palisade-parenchyma; while simple leaves and 

 those having large segments possess only a single layer of paren- 

 chyma. In the case of linear divisions, the parenchyma is con- 

 tinued around the marginal nerve and tends to invade the lower 

 face. The following table indicates the wide difference which 

 exists in the amount of assimilative activity. The species first 

 mentioned, Angelica silvestris, has large segments: the species 

 compared with it has in each case smaller divisions of the leaves, 

 but these are thicker. 



C.C. C.C. C.C. 



T j Angelica silvestris j 0-102 j 0*112 j 0-140 



\ Libanotis montana \ 0-159 ' ( 0-166 ' ( 0-240 



Angelica silvestris . j 0-087 g j 0-091 j 0*110 



Peucedanum Oreoselium ' ( 0-286 ' / 0*241 ' ( 0-240 



• Angelica silvestris n j 0-068 j 0*076 \ 0'084 



[ Peucedanum Parisiense \ 0-232 ( 0-252 ( 0*380 



The numbers denote the amount of carbonic acid (expressed in 

 cubic centimeters) absorbed in one hour. G. l. G. 



"•I 



