834 General Notes. [October, 



nal cusp of the fourth superior premolar is connected with the 

 anterior and posterior cingula by strong ridges, becoming thus 

 the apex of a V. In the P. siibquadrata it is a simple cone. An- 

 tero-external basal lobe distinct, intermediate lobe obsolete. The 

 true molars are like those of the P. siibquadrata, but all the 

 molars are of smaller size. Length of P-m. iv, plus M n and M. 

 in, .0215; diameters P-m. iv ; anteroposterior, .006 ; transverse, 

 .007 ; do. of M. 11, .0095 and .008. D. Baldwin. 



Dissacus camifex, sp. nov. — This creodont differs from its only 

 congener in its greater size, and in the presence of an anterior 

 basal lobe on the third inferior premolar. This is wanting in D. 

 Jiavajovius. As compared with the latter the six inferior molars 

 are as long as its seven, and the mandibular ramus is much 

 deeper. Like it the P-m. iv and the true molars have an anterior 

 basal tubercle : and the last two true molars have an internal 

 supplementary cusp. After the Sarcotlwausles antiquus, the 

 largest flesh-eater of the Puerco. Length of last six molars, 

 .075 ; of true molars, .038; of P-m. iv, .0125 ; of M. n, .0135 ; 

 of M. in, .0130. Depth of ramus at M. 11, .029. Upper Puerco, 

 D. Baldwin.— E. D. Cope. 



Geological News — The July number of the American Jour- 



metalliferous vein formation now in progress ;it Sulphur Bank, 

 near Clear lake, Cal., including a description of the geology of 

 the vicinity, by Professor Joseph Le Conte. To the same maga- 

 zine Rev. A. A. Young contributes observations on the crystal- 

 lized sands of the Potsdam sandstone of Wisconsin ; and G. K. 

 Gilbert writes upon the origin of jointed structure, combating the 

 theory of Professor John Le Conte, who in the March number of 

 the same magazine explains the jointed structure of the Quater- 

 nary clays of the Great Salt Lake desert by referring it to the 

 same category with shrinkage cracks observed in recent Califor- 

 nian alluvial deposits. Shrinkage cracks form four to seven sided 

 irregular masses, the included angles varying greatly, whereas 

 the joints of indurated rocks are characterized by parallelism, 

 and the lines of two systems of joints cross each other, which is 

 not the case in shrinkage cracks. Mr. Gilbert then takes up the 

 theory which classes joints with slaty cleavage, ami attributes 

 them to lateral compression. As it appears improbable that a 

 broad sheet of fresh-water sediments, so fresh that the shore- 

 trace of the formative lake has scarcely been impaired by the 

 weather, should have been lateral lv compressed in two directions 

 nearly at right angles to each other so as to form the two systems 

 of joints which exist in it, and as, moreover, onlv a single system 

 of joints exists in the Triassic and Jurassic sandstones of the 

 Colorado plateaus, Mr. Gilbert dismisses this theory also as un- 

 tenable, and regards the question as still an open one. the 



