July IS, 1884.; 



SCIENCE, 



71 



areas of extinction have been areas where the 

 old river-courses have changed or dried up ; 

 and these, according to Powell and Dutton, 

 are comparatively few. An interesting line 

 of research suggests itself here, which lack of 

 material may prevent at present, upon the 

 divergence of structural characters after the 

 separation of the eastern and western fauna 

 by the Rocky-Mountain system. 



Professor Marsh's paper upon birds with 

 teeth contains little that did not appear in 

 his monograph, ' Odontornithes : ' it is, in fact, 



an abstract of that volume, with the omission 

 of many details of structure. There have 

 been added, however, several characters to 

 Archaeopteryx, which the author himself dis- 

 covered upon the European specimens. It is 

 an astonishing fact, worth mentioning here, 

 that in many foreign museums it is still con- 

 sidered more important to preserve these speci- 

 mens intact than to publish the rich truths they 

 might reveal under a careful use of the ham- 

 mer and chisel. 



INTELLIGENCE FROM AMERICAN SCIENTIFIC STATIONS. 



GOVERNMENT ORGANIZATIONS. 



U. S. geological survey. 



Rocks from Oregon. — During the field-season of 

 1883, Mr. Frank Wood, a stone-cutter in Albany, 

 Or., contributed to the Cascade-Kange collection of 

 rocks several specimens of stone used extensively in 

 that part of the country for building and ornamental 

 purposes. They were examined by Mr. J. S. Diller, 

 and proved to be of unusual interest, not only on 

 account of their economic value, but also for their 

 bearing upon the geological history of the Cascade 

 Kange. 



Among them was an eruptive rock, which is quar- 

 ried twenty miles east of Albany, on the western 

 slope of the Cascade Eange, and which presents an 

 ancient aspect. The composition of this rock is that 

 of a diabase with an admixture of rhombic pyroxene ; 

 but in its general facies and structure, as well as in 

 the character of its alteration products, it is closely 

 related to the gabbros. Kocks of the same character, 

 high up in the mountains, are abundant a short dis- 

 tance south-west of Mount Hood. While it has long 

 been known that the Cascade Range is built up chiefly 

 of recent lavas, it is becoming more and more evi- 

 dent that eruptions of gabbroic and granitic rocks 

 must be admitted as important elements in its con- 

 struction. 



On the Willamette River, eight miles from Albany, 

 a sandstone is quarried which belongs to the ter- 

 tiaries of the Willamette valley, and, with the excep- 

 tion of the cementing-material, is composed wholly 

 of volcanic matter. When first taken from the quar- 

 ry, it is said to be soft, and easily carved into any 

 desired shape. Upon exposure, it becomes hard and 

 more durable. This change in its physical character, 

 so far as can be judged from the hand specimen in 

 the collection, appears to be connected with a pecul- 

 iar alteration in its cement. The unaltered sand- 

 stone, when held in such a position as to reflect the 

 light from its surface, is seen to have a peculiar shim- 

 mer, which, upon closer examination, is found to 

 come from the brilliant cleavage-surfaces of the well- 

 crystallized calcite which forms the cement. The 



rock splits quite readily in three directions. Follow- 

 ing these lines of easiest cleavage, a small rhombo- 

 hedron was split out of the sandstone, which showed 

 the peculiar shimmer on all sides. With an impro- 

 vised goniometer, the angles between the reflecting 

 surfaces were measured, and found to be the regular 

 cleavage-angles of calcite. In the thin section it 

 could readily be seen that the calcite cement had the 

 same optical orientation throughout. There can be 

 no doubt that all the calcitic cement within the hand 

 specimen belonged essentially to the same crystal. 

 Professor Irving has shown that siliceous cement in 

 sandstone is very frequently arranged with reference 

 to the crystallographic axes of the quartz-grains which 

 it envelops. It is much less common, however, to 

 find the cement arranged as in this Albany sand- 

 stone. That carbonate of lime can arrange itself in 

 one crystal, when mixed with from fifty to sixty per 

 cent of sand, is clearly shown by the well-known 

 crystals from Fontainebleau and Nemours, in France. 

 Under atmospheric influences, the calcitic cement 

 appears to be replaced by one which is in large part 

 siliceous. The boundaries of the grains of sand 

 become less distinct, and the cement assumes a 

 spherulitic structure. To be able to assert positively 

 that this peculiar structure in the cement of a sedi- 

 mentary rock is due to weathering, our observations 

 with the microscope need to be supplemented by an 

 examination of the rock in situ at the quarry. The 

 rock, therefore, becomes more durable, being insolu- 

 ble, and is much less liable to injury from great and 

 sudden changes of temperature. 



Krakatoa dust. — A report by Mr. Diller, on the 

 Krakatoa dust submitted to him for examination, 

 has been completed. Reusch determined the rhom- 

 bic pyroxene in the Krakatoa dust to be bronzite, 

 while Daubree, Renard, and others have asserted 

 that it is hypersthene. Although Mr. Diller obtained 

 the dust from four different localities, enough was 

 not received to furnish sufficient rhombic pyroxene 

 for chemical analysis to settle the question; and with- 

 out a. Norrenbergs apparatus, or a microscope with 

 a larger field than the one used by Mr. Diller for the 

 observation of optic axial figures, so that the char- 



