20 THE AMERICAN MONTHLY. [January. 



Button. 2. Preliminary Paper on the Driftless Area of the Upper Mississippi Valley, 

 by T. C. Chamberlain and R. D. Salisbury. 3. Quantitative Determination of Silver 

 by means of the Microscope, by J. S. Curtis. 4. Sea-Coast Swamps of the Eastern 

 United States, by N. S. Shaler. 5. Synopsis of the Flora of the Laramie Group, by L. 

 F. Ward. These papers are all thoroughly illustrated ; the last by 34 double-page plates, 

 illustrating about 150 species and many genera. The paper of greatest interest is the 

 second upon the driftless area of 10,000 square miles in Wisconsin and adjoining States. 

 If this area were higher than the level of the surrounding drift-covered area, it would 

 be easily imagined that the area was, during the glacial period, a huge summit above 

 the glacial level. ' Strangely enough the margin of the drift, on almost every hand, 

 hes on a slope descending toward the drifdess area. The drift-bearing ice was stayed 

 in its course, not by some great topographic barrier it could not overcome, but by some 

 agency that arrested it in its downward career on the slopes toward the unglaciated 

 basin.' The itudy of this problem is continued by the author through six chapters 

 and 120 quarto pages, in which the general topography and stratigraphy of the region 

 are considered, also preglacial degradation and residuary products, circumjacent gla- 

 cial phenomena, the loess and terraces, finally, the history and genesis of the area in- 

 quired into. The general conclusion, broadly stated, is that the area hes beneath the 

 lee of high lands to the north, which diverted the glacial stream from the driftless area. 



A Shidy of the Histological Characters of the Periosteum and Peridental Membrane. 

 By G. V. Black, M. D., D. D. S. 71 figures, W. T. Keener, Chicago. One vol- 

 ume, octavo, muslin, $3.00. 



The Dental Review is to be congratulated upon being able to publish in its columns 

 so valuable a work as this. From the character of the descriptive text, as well as 

 from the great value of the figures, it is plainly one of the leading works of refer- 

 ence in this department of histology. The completed series of articles are now 

 published in book form by W. T. Keener, of Chicago. They form a treatise upon the 

 above-mentioned topic, giving precise directions for technical handling for section 

 cutting, and a very careful examination of the complete histological structure. 



The illustrations, 71 in number, are deserving of the highest credit for the pains 

 which must have been taken both to prepare the original sections and to execute the 

 drawings. 



Exchanges. 



[Exchanges are inserted in this column without charge. They will be strictly limited to mounted objects, and 

 material for mounting.] 



Wanted, Diatomaceous earth from Megillanes, Bolivia, South America. Can give in exchange either Dia- 

 tomaceous earth from New Zealand or cash. E. MICHALEK, 



I. Fleischemarkt, No. i, Vienna, Austria. 

 Mounted sections of Foetal Lung (5 months), sections across entire lobe, ^^^ in. thick, beautifully stained, in 

 exchange for first-class pathological slides. W. C. BORDEN, M. D., U. S. A., 



Fort Douglas, Utah. • 

 Correspondence relative to exchange in microscopical material or prepared mounts. 



HENRY L. OSBORN, Hamline, Minn. 

 Wanted, earths, recent diatoms, and miscellaneous objects for mounting. Only first-class material offered or 

 desired. MARY A. BOOTH, Longmeadow, Mass. 



Fossil Diatomaceous deposits (marine) wanted from Bermuda, Virginia, Maryland, California, etc. 



I. ELLIOTT, Ardwyn Villa, Aberj-stwith, Wales, England. 



Notices. — All communications for publication should be addressed to Henry Leslie Osborn, Hamline 

 University, Hamline, Minn. 



Subscriptions, and all matters of business, should be addressed to the Manager, Chas. W. Smiley, P. O. 

 Box 630, Washington, D. C. 



Subscription price $1.00 PER YEAR- strictly in advance. All subscriptions should end ivilh the De- 

 cember number. A pink wrapper indicates that the subscription has expired. A date on the wrapper in- 

 dicates the month to which payment has been made. 



Orders for slides advertised by A. J. Doherty in the Journals from January to April, 1887, may be sent 

 through the Business Manager, P O. Box 630, Washington, D. C. 



A few copies of Leidy's Fresh-Water Rhizopods, of North America, can still be had at $5 00 per copy. — P. 

 O. Box 630, Washington, D. C. 



Remittances should be made by postal notes, money orders, or by money sent in registered letters. -Drafts 

 should be made payable in Washington, New York, Boston, or Philadelphia, to the order of the Manager. 



The first volume, 1880, is entirely out of print. The succeeding volumes will be sent by the publisher for 

 the following prices which are net: — Vol. II (1881) complete, $1 50 ; Vol. Ill (1882), out of print ; Vol. IV 

 (1883) complete, gi.50; Vol. V (1884) complete, $1.50; Vol. V (1884), Nos. 2-12, Ji.oo; Vol. VI (1885), gr.50 ; 

 Vol. VII (1886), Si. 00; Vol. VIII (1887), $1.00. As calls for Volume I sometimes occur, those persons having 

 copies to dispose of would do well to inform us, and to state their prices. 



