March 16, 1883.] 



SCIENCE. 



177 



ble results. — {Biedermann' s centr.-blatt., 1882, 735.) 



H. P. A. [371 



GEOLOGY. 



Impressions on Potsdam sandstone. — At the 

 meeting of the Natural history society of Montreal, 

 Feb. 26, Mr. Walter Ferrier exhibited specimens of 

 some new trails and impressions of animals from the 

 Potsdam of Rainbow Falls, near Au Sable chasm on 

 Lake Chainplain. One of them is a cast of two nar- 

 row furrows about a quarter of an inch apart, with a 

 rim of punctiform impressions about an inch distant 

 at either side. This impression is repeated in two 

 places on a ripple-marked slab. It may be the track 

 of a trilobite Avith two prominent spines on the pygid- 

 ium, possibly of some species of Dikellocephalus. 

 Another is a trail about an inch in width, marked 

 with transverse furrows and ridges, perfectly simple, 

 and without any median ridge. In this last respect 

 they differ from the trails known as Eurichnites, 

 Cniziaua, Arthrichnites (Arthrophycus), and Traena. 

 They resemble, though on a larger scale, impressions 

 from the Brian sandstone of Gasjie, of whicli a slab 

 from the collection of Dr. Dawson was exhibited for 

 comparison. Such impressions, destitute of a cen- 

 tral ridge, may have been made by gasteropods or by 

 worms without any abdominal furrow. The name 

 Clydichnites (wave.- tracks) has been proposed for 

 them by Dr. Dawson; and the Potsdam and Brian 

 forms must belong to two distinct species. — J. w. D. 



[372 



Newfoundland geology. — The report of prog- 

 ress of the Geological survey of Newfoundland for 

 the year 1881 contains a report of Mr. J. P. Howley 

 on the structure of tlie peninsula of Avalon. He 

 finds that the major part of the peninsula is made up 

 of tlie various divisions of the Huronian or Interme- 

 diate system, as given in the report for 1S6S, resting 

 upon a nucleus of gneiss, and succeeded by the fossil- 

 iferous beds of the primordial Silurian or Taconic, 

 which skirt the shores of the bays, and form most of 

 the islands tlierein. In division d of the Huronian 

 system the fossils Aspidella terranovica and Arenic- 

 olites spiralis occur. He recognizes two large in- 

 trusive masses of plutonic rocks, — one in the eastern, 

 and tlie other in the western peninsula. That in the 

 eastern peninsulahe considers the older, as it has not 

 affected the primordial strata, as has been the case in 

 the western peninsula. The eruptive mass between 

 Salmon cove and Collier's bay he considers as liav- 

 ing been formed prior to the deposit of the higher 

 members of the Huronian system, as the strata inter- 

 sected are confined to the lower divisions, a and b. 

 Mr. Howley failed to discover, in the auriferous 

 quartz-veins of division c, a single example of visible 

 gold. Some copper ores were found, mostly in divis- 

 ions a and 6 of the Huronian system. Near Little 

 Placentia, some argentiferous galenite occurred, 

 which yielded, on analysis, 159 ounces of silver to 

 the ton (2,240 pounds) of ore. Accompanying the 

 report is an appendix with three plates, containing 

 descriptions and figures of primordial fossils, by the 

 late E. Billings. These figures and descriptions have 

 already been published {Geol. surv. Can., pal. fosa., 

 1874, ii. 1). A geological map on a scale of four miles 

 to the incli, and showing very plainly the distribu- 

 tion of the formations, accompanies this report; also 

 a section-map showing the corrugations effecting the 

 stratification of the Huronian formation near Brigus, 

 Conception bay, on a scale of four inches to a mile, 

 surveyed by J. P. Howley. — J. b. m. [373 



Lithology. 



Hunting for lost glaciers •with a micro- 

 scope. — Considerable work has been done in this 



direction in Germany and elsewhere by various ob- 

 servers, — work with which geologists are more or 

 less familiar. 



In the present paper the results of an extended 

 study of the plagioclase rocks and phonolites of the 

 Mecklenburg drift is given by one of the prominent 

 young German lithologists, — Dr. Engen Geinitz, of 

 the Rostock university. Geinitz' method consists in 

 examining thin sections of the rocks found in the 

 drift, and comparing them with the descriptions given 

 by the Scandinavian lithologists of rocks known in 

 uiu in that peninsula. In this way various basalts, 

 diabases, gabbros, diorites, and phonolites are re- 

 ferred to certain localities in Sweden, whence they 

 are supposed to have been derived. Interesting re- 

 sults can be obtained by such methods; but they are 

 often uncertain, since it cannot be predicated that 

 rocks of the same character do not exist, or have not 

 existed, in the intermediate drift or water-covered 

 areas. 



The paper is a valuable one on account of the ex- 

 tended descriptions of the rocks examined. — {Nova 

 acta acad. leop. -carol, x\y. 36.) m. e. w. [374 



Hypersthene-andesite. — The chief pyroxene of 

 an apparently typical ' augite-andesite' from Buffalo 

 Peaks, Col., was found by Whitman Cross to be 

 hypersthene, both from its optical properties and 

 chemical composition. The mineral was isolated for 

 analysis by treating the rock powder with HFl, 

 which dissolved the feldspar, glass base, and finally 

 the augite, leaving only the hypersthene (richer in 

 iron than augite) and ore particles. The latter, being 

 magnetite, were separated by a small magnet. The 

 microscopic examination of many Buropean and 

 American augite-andesites of the same tyjie seems to 

 prove that they, likewise, contain more rhombic py- 

 roxene (hypersthene) than augite; and Cross claims 

 that they should be separated from other andesites, 

 and called 'hypersthene-andesites.' Nearly all other 

 so-called augite-andesites have more of the trachytie 

 habitus, and are so nearly related to hornblende and 

 mica-bearing andesites, that, according to the writer, 

 they cannot be consistently separated, and considered 

 as a distinct group. Should the determination of 

 hypersthene in this sub-group of the andesites be 

 confirmed, a very interesting, widely distributed, and 

 well defined rock-type will have been discovered. — 

 {Amer.journ. sc, Feb., 18S3.) s. F. E. [375 



METEOROLOGY. 

 lo'wa Tweather service. — -Mr. Gustavus Hinrichs 

 has issued an almanac for 1883, under the title of Iowa 

 weather service annual, giving, in addition to the or- 

 dinary calendar, a summary statement of the climate 

 of Iowa, illustrated by several diagrams. The mean 

 temperature for Iowa City is, for the winter months, 

 25°; for the summer, 72°. The barometer is highest 

 in December, lowest in April and June. The winds 

 are strongest in March and April, being mostly west- 

 erly or north-westerly in winter, often easterly in 

 spring, southerly or calm in summer, and westerly in 

 autumn. Besides the general cyclonic storms, Iowa 

 has the 'blizzard,' an intensely cold, high wind fol- 

 lowing a winter thunder-storm ; the tornado, com- 

 monest in June, but occurring from March to 

 October; and the squall, a sudden north-westerly 

 wind with heavy clouds and rain, following sultry 

 weather with light southerly winds. Precipitation is 

 greatest from June to August, and least in December. 

 It is sho'mi on monthly maps compiled from 26,082 

 measures from 1876 to 1880. It is least in the north- 

 west (26"), heaviest in the south (36") and east (38"), 

 and seems to be " dependent on the distribution of 



