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moid curve, the halves of which are from vation of the peneplain. In places the inone-half to three-fourths of a mile in diam- creased velocity may have straightened the eter. The rock neck of land between the curves to some extent. In other instances two ends of the closer curve is less than a the meanders have been somewhat inhundred yards in width and rises about creased. Such seems to have been the case seventy feet above the stream.

near Benton, where the stream is now underAlong Platte, Little Platte, Grant and cutting the narrow strip of land separating Pecatonica rivers, larger streams than Fever two parts of the curve. If this process conriver, the meanders are slightly larger on tinues, a cut-off will result. the average than along the smaller streams. In comparison with the Osage river, these Both open and close curves occur. Rock streams are small and their meanders insalients between 100 and 200 feet high pro significant. But apart from size, the analogy ject into the bow of each meander. Almost between them is complete. They must be as complete a series of meander types can added to the growing list of streams known be found among the curves of the rock val- to be persisting in habits acquired under leys of these rivers as along the broad conditions which have long since disapflood-plains of other streams. Indeed, the peared.

HENRY B. KÜMMEL. small meanders of these rivers in their pres

THE UNIVERSITY OF CHICAGO. ent flood-plains can readily be duplicated by the wider curves of the rock valley.

CORRESPONDENCE. There can be no reasonable doubt but that

MISSOURI ROTANICAL GARDEN. the meanders of these valleys are an in- The attention of botanists is called to the heritance from meanders developed on broad facilities afforded for research at the Misflood-plains in a previous cycle of erosion. souri Botanical Garden. In establishing So far as could be made out, these mean- and endowing the Garden, its founder, ders are not due to difference in hardness Henry Shaw, desired not only to afford the or structure of the rocks of the region. general public pleasure, and information The limestone does not present sufficiently concerning decorative plants and their best marked differences of structure to account use, and to provide for beginners the means for these curves upon a theory of readjust- of obtaining good training in botany and ment of courses due to the contrasts be- horticulture, but also to provide facilities tween hard and soft beds. Whatever dif- for advanced research in botany and cogferences exist are not distinctly such as to nate sciences. For this purpose, additions modify the courses of rivers, particularly are being made constantly to the number in a manner such as to resemble so closely of species cultivated in the grounds and flood-plain meanders. Nor does it seem to plant houses, and to the library and herbe admissible to suppose that these curves barium, and, as rapidly as it can be utilized, are the perpetuation of meandering courses it is proposed to secure apparatus for work taken when the land first emerged from the in vegetable physiology, etc., the policy sea bottom. Such a supposition presup- being to secure a good general equipment in poses too constant and stable a relationship, all lines of pure and applied botany, and to through an enormous lapse of time be- make this equipment as complete as postween all the forces which control erosion sible for any special subject on which ori. and determine the position of streams. ginal work is undertaken by competent

The sinuosities of these meanders may students. have been somewhat changed since the ele- A very large number of species, both

native and exotic, and of horticulturists' plants and the modifications they have varieties, are cultivated in the Garden and undergone. Arboretum and the adjoining park, and the These facilities are freely placed at the native flora easily accessible from St. Louis disposal of professors of botany and other is large and varied. The herbarium, which persons competent to carry on research includes nearly 250,000 specimens, is fairly work of value in botany or horticulture, representative of the vegetable life of subject only to such simple restrictions as Europe and the United States, and also are necessary to protect the property of the contains a great many specimens from less Garden from injury or loss. Persons who accessible regions. It is especially rich in wish to make use of them are invited to material illustrative of Cuscuta, Quercus, correspond with the undersigned, outlining Coniferae, Vitis, Juncus, Agave, Yucca, with as much detail as possible the work Sagittaria, Epilobium, Rumex, Rhamnaceæ they desire to do at the Garden, and giving and other groups monographed by the late timely notice so that provision may be Dr. Engelmann or by attachés of the made for the study of special subjects. Garden. The herbarium is supplemented Those who have not published the results by a large collection of woods, including of original work are requested to state their veneer transparencies and slides for the preparation for the investigation they promicroscope. The library, containing about pose to undertake. 8,000 volumes and 10,000 pamphlets, in- Under the rules of Washington Univercludes most of the standard periodicals and sity, persons entitled to candidacy in that proceedings of learned bodies, a good col- institution for the Master's or Doctor's delection of morphological and physiological gree may elect botanical research work as works, nearly 500 carefully selected botan- a principal study for such degrees, if they ical volumes published before the period can devote the requisite time to resident of Linnæus, an unusually large number of study.

WILLIAM TRELEASE, monographs of groups of cryptogams and St. Louis, Mo.

Director. flowering plants, and the entire manuscript notes and sketches representing the pains

SCIENTIFIC LITERATURE. taking work of Engelmann.

THE GEOLOGY OF THE SIERRA NEVADA. The great variety of living plants repre- Geologic Atlas of the United States. U. S. sented in the Garden, and the large her- Geological Survey; J. W. POWELL, Dibarium, including the collections of Bern- rector. Sacramento Folio, Geology by W. hardi and Engelmann, render the Garden LINDGREN. Placerville Folio, Geology by facilities exceptionally good for research in W. LINDGREN and H. W. TURNER. Jackson systematic botany, in which direction the Folio, Geology by H. W. TURNER. Washlibrary also is especially strong. The living ington, D. C. 1894. collections and library likewise afford un- These three sheets are the first installment usual opportunity for morphological, ana- of a series covering the gold belt of Calitomical and physiological studies, while the fornia which has been in course of preparaplant house facilities for experimental work tion for several years by the officers of the are steadily increasing. The E. Lewis Geological Survey. It is needless to say Sturtevant Prelinnean library, in connection that they form a very important and welwith the opportunity afforded for the culti- come contribution to our knowledge of the vation of vegetables and other useful plants, geology of California. Since the collapse is favorable also for the study of cultivated of the old State Survey under Whitney, but little effort has been made by California only bring serious discomfiture to the Geoto elucidate her economic geology, notwith logical Survey as a government institution. standing the liberal appropriations which The Sacramento, Placerville and Jackson the State Legislature makes regularly for folios bring out clearly the salient features the maintenance of a so-called Mining of a section which may be taken as typical Bureau.' In the knowledge of her geologic for the western slope of the Sierra Nevada. resources, California is far behind many The Sierra slope rises from the eastern edge minor States of the Union. It is therefore of the Great Valley of California to the fortunate that the Federal authorities have crest of the range, some 60 miles distant at so steadily prosecuted the inquiry into the an inclination of less than 2°. It presents the geology of the gold belt of the Sierra characters of a gently tilted plain which Nevada and of other portions of northern has been incisively dissected by the streams California. The sheets under review are which traverse it. This slope is underlain the results of this work. They form part by two very different assemblages of rocks. of the geologic atlas of the United States The first of these is composed of sedimentand they are among the first dozen of the ary and eruptive formations which have entire series. The mechanical execution of been intensely disturbed, metamorphosed the folios challenges the admiration of all and invaded by vast intrusions of granitic familiar with such work. In the opinion magma, forming a complex whose eroded of the writer they compare very advantage- surface serves as the basement upon which ously with the best European efforts of a the second assenıblage reposes in little dissimilar kind. It is gratifying to American turbed attitudes. The older assemblage is pride to see the beginnings of so vast a designated in the folios the 'Bed-rock' sescientific project as a geologic atlas of the ries, and the newer, the 'Superjacent' seUnited States realized in a manner so emi- ries. Neither of these terms is felicitous, nently satisfactory. If there exists a doubt although the first is based on popular usage in the minds of the geologists of the country, and will appeal to the mining community. and in this case the geologists speak for the The Bed-rock series comprises the rocks people, as to the ultimate success of the which are known popularly as the auriferproject, it is based on the fear that there ous slates, together with their associated may not be in the future, as there certainly eruptives and irruptives, and also the granhas not been in the past, a proper coördina- itic rocks which invaded the series as a tion of the topographic and the geologic whole at the close of the Jurassic. It would branches of the survey. A correct topo- be better if these granitic intrusions were graphic base is the sine qua non of a good not classed in the same category with the geologic map; and unfortunately the topo- auriferous slates as part of a 'series. The grapher's conception of a correct map, in auriferous slates comprise the Calaveras forthe present state of his professional educa- mation (Carboniferous, with possibly some tion, is not what it ought to be. Thorough older Paleozoic) and the Mariposa formaand conscientiously executed topographic tion. In the earlier Sacramento and Plasurveys are expected of the geological sur- cerville folios, which are chiefly Lindgren's vey. The ambitious extension of the topo- work, the Mariposa formation is colored as graphic surveys far in advance of geologic Cretaceous, while in the later Jackson folio investigation, at a rate which not only abso- by Turner the same formation is colored as lutely precludes the possibility of thorough Jurassic. The reference of this formation work but demoralizes the topographer, can to two different horizons can scarcely be

taken as indicative of decided difference of logical map is handicapped by not having opinion between these two geologists, but the effusive rocks discriminated from the rather of a rapid change of opinion on the intrusive on the color scale. From the text part of the officers of the survey in conse- it is apparent that many of the igneous quence of the recent paleontological deter- rocks are clearly intrusive, while others are minations of Hyatt, whose results were

effusive. This discrimination should be probably not available at the time the earlier expressed graphically, as it is impossible to folios went to press. The Mariposa formation understand the structure without keeping is of economic importance as that in which it in mind. The doubtful rocks should be occurs the zone of auriferous veining which grouped apart from those which are clearly constitutes the famous Mother Lode.' effusive or intrusive. An extra convention

In a field so overburdened with igneous or two to express doubt or ignorance on rocks, contemporaneous and intrusive, particular points would greatly enhance the geologists will readily understand that scientific value of our geological maps. many problems arise which are not easily One of the most important features of the answered by the most earnest efforts of the Sierra Nevada slope is the invasion of the field geologist. The lack of definite state- Calaveras and Mariposa formations by the ments as to the structural relations of the Sierra Nevada batholite. The relations of various sedimentary and igneous forma- the older rocks to this invading magma are tions indicates that these relations are ob- beautifully brought out by the careful mapscure and difficult to determine. Still, a ping of Messrs. Turner and Lindgren. brief statement from Messrs. Turner and Petrographically, the rocks of this batholite Lindgren as to the interpretation of their are chiefly of a type intermediate between structural sections would have been a de- granite and diorite, and are therefore desigsirable addition to the letter

press, which is nated as granodiorite. Other important limited strictly to historical, petrographic facies of the same magma are granite, gaband economic geology. For example : Are bro and gabbro-diorite. These rocks apthe two belts of the Mariposa slates on the pear as great intrusive areas in the midst of Jackson sheet essentially synclinal troughs the auriferous slates and establish prowith an anticline bringing up a belt of the nounced zones of contact metamorphism in lower Calaveras between them? If so, the the latter. Putting the three geologic sheets structure is comparatively simple, and the together, and bearing in mind the distribugreat body of amphibolite schist, diabase tion of these same granitic rocks to the and porphyrite probably represents vol- eastward and southeastward of the area canic accumulations chiefly intermediate in mapped, it is difficult to resist the suggesage between the Calaveras and the Mari- tion that these rocks underlie practically posa, but perhaps passing up into the lat- the whole of the Sierra slope beneath the ter. Or is the region traversed by a great rocks through which they project as isolated system of longitudinal faults? A discus- masses.

In other words, the mapping sugsion of these and other tectonic questions gests strongly that if the plane of truncation we may doubtless expect in more detailed effected by erosion had been lower a much reports upon the geology of the region. larger proportion of granite would have But something of the tectonic should find a been exposed, and if higher less. If this place in the folios to help out the sections. suggestion be accepted it follows that the While alluding to the igneous rocks it may Calaveras and Mariposa formations must be well to mention that the user of the geo- have reposed upon the granodiorite magma


as a crust, up into which the magma On the [Harvest Mice] Species of the Genus advanced, not only by displacement, but Reithrodontomys. By J. A. ALLEN. 8° absorption. For we have no trace appar- May 21, 1895. From Bull. American ently of the original basement upon which Museum of Natural History, New York the Calaveras formation was deposited. In (pp. 107-143). these relations of batholite to disturbed and Dr. Allen has just published a much metamorphic crustal rocks we have a strik- needed revision of the Harvest Micea ing analogy with the relations which obtain group of small mammals differing from other between the Laurentian granites and the murine rodents in having the upper incisors metamorphic rocks of the Ontarian system deeply grooved. Since Dr. Allen's study is in the Lake Superior region. The amphi- based on upwards of 900 specimens (twobolites and other schists of "auriferous thirds of which belong to the rich collection slates’ are petrographically the same of the U. S. Department of Agriculture) it many of the schists of the Ontarian system. is probable that future researches will add

The invasion of the Jurassic and earlier little to the results here published, so far rocks by the Sierra Nevada batholite seems as the United States forms are concerned. to have been accompanied, or perhaps pre- The name of the common species of the ceded, by uplift and the development of Carolinas is changed from humilis to lecontei. mountain structure. During early Cre- Fifteen species and subspecies are recogtaceous time these mountains were pro- nized, 12 of which inhabit the southern and foundly eroded, for on the edge of the valley western parts of the United States. Seven of California we find the Chico Cretaceous, of the United States forms are accorded full the earliest of the Superjacent' series, re- specific rank. One of these, R. montanus of posing upon the worn surface of the grano. Baird, is known from the type specimen diorite. The Chico is followed by the Ione only, which was collected in Colorado more and later Tertiary formations. In part con- than 40 years ago and is in very poor conditemporaneously with the Ione, but chiefly tion. When additional specimens are obat a later period, there were spread over tained from the type locality it will probably portions of the region important sheets of displace one of the other species. Another, gravel. Associated with these are flows R. arizonensis from the Chiricahua Mounof rhyolite and andesite. The rhyolite tains, is separated from R. longicauda of flows serve as a means of separating the California, chiefly on geographic grounds. older' from the 'later' gravels. The an- In the case of one of the subspecies addesitic flows were contemporaneous chiefly mitted—R. longicaudus pallidusit is not with the first of the later gravels. These likely that Dr. Allen will be followed by gravels constitute the once famous placers other mammalogists. Respecting this form of California. Since they were spread over he says: “I find myself greatly embarrassed the Sierra slope, the latter has been tilted so as to which of three courses to pursue in as to accentuate the grade and intensify the the matter, namely: (1) To refer R. pallidus downward corrasion of the streams. As a to R. longicauda as a pure synonym of the consequence of this corrasion, we now find latter; (2) to treat R. pallidus as one of sevonly remnants of the gravels and volcanic eral local phases of R. longicauda; (3) to flows reposing on the tops of nearly flat let the name stand in a subspecific sense ridges between the river gorges.

for a generally dispersed paler southern ANDREW C. LAWSON. form of R. longicauda, as opposed to true UNIVERSITY OF CALIFORNIA.

longicauda of the region from about Monterey

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