62 



SCIENCE. 



[N. S. Vol. V. No. 106. 



TJ. S. National Museum, Vol. VII., p. 99; Am. 

 Journal of Science, Sept., 1886. Tliese refer 

 to the region in questiou. Closely similar de- 

 posits have been found as far east as Omaha, 

 and as far north as the Missouri River in Knox 

 Co., Neb. 



An interesting and important question vs'hich 

 should be kept in mind by those observing these 

 deposits is whether there is more than one 

 horizon shown at any one locality. Thus far 

 I think no one has reported more than one, 

 and it may be that all are to be referred to one 

 eruption. If so the deposit becomes a most 

 important reference horizon. 



As a related item of intelligence I may add 

 that this last summer I discovered a deposit of 

 somewhat similar character extending a dozen 

 miles or so along the South Fork of White 

 River, in Lugenbeel Co., S. D., showing a thick- 

 ness in places of more than 10 feet. This 

 deposit is, however, of a light green color, 

 coarser than that of Nebraska and more con- 

 solidated than I have seen there. Moreover it 

 seems to mark the transition from the White 

 River epoch to the Loup Fork. 



J. E. Todd. 



State XJniveesity, 



Vermilion, S. D. 



SCIENTIFIC LITERATURE. 

 GRASSES OP NORTH AMERICA.* 

 The botanists of this country have been look- 

 ing forward with interest for several years to 

 the publication of the second volume of Dr. 

 Real's 'Grasses of North America.' Single- 

 handed and alone, away from the larger libra- 

 ries and collections, Dr. Real has patiently and 

 persistently carried forward the work which 

 he has finally brought to completion and pre- 

 sented to the public in the volume before us. 

 Much interest attaches to the work, for we have 

 here presented, for the first time, in a single 

 volume, descriptions of all the grasses of the 

 United States and northward, which the writer 



*Grasf:es of North America, by "W. J. Beal, M. A., 

 M. S., Ph.D., Professor of Botany in the Michigan 

 Agricultural College, Vol. II. The grasses classified, 

 described, and each genus illustrated, with chapters 

 on their geographical distribution and their bibliog- 

 raphy. Henry Holt & Company, New York. 



was able to obtain, together with those which 

 have in recent years been collected in Mexico 

 by Mr. C. G. Pringle and Dr. E. Palmer. No 

 work of similar character has before been pub- 

 lished, and those wishing to find descriptions of 

 our grasses, excepting for limited areas, have 

 been obliged to consult numerous publications 

 through which the descriptions were scattered. 

 The total number of species described in the 

 work, including introduced species and those 

 cultivated for use or ornament, is 912, covering 

 659 pages. With few exceptions, these descrip- 

 tions, which are very full, have been originally 

 drawn up by the author. The nomenclature 

 adopted is that of the so-called 'Rochester code,' 

 and in every case full citations of authorities 

 are given, considerable space being devoted to 

 synonymy. 



The author states in his preface that ' ' it has 

 required some courage and persistence to ad- 

 here to the work so long, realizing fully that 

 it must contain many defects, and that per- 

 haps its chief use would be to serve as a basis 

 for others to enlarge in the future, correct and 

 otherwise improve. ' ' This is very often the fate 

 of scientific publications, and no one can hope 

 to produce a work of any considerable extent 

 which shall be beyond criticism or entirely free 

 from errors. The work before us is no excep- 

 tion to this statement, and the criticisms or cor- 

 rections here given are made in the kindliest 

 spirit, with the intent of calling attention to 

 some of the more important mistakes, hoping 

 thereby to enhance the usefulness of the work, 

 rather than discredit its value. 



Collectors in preparing their labels occasion- 

 ally overlook the importance of carefully noting 

 the locality and station of the specimens gath- 

 ered, and more often still they fail to note the 

 date of collection or altitude. It is almost dis- 

 couraging, and even annoying sometimes, to 

 look over a dozen or more sheets of specimens 

 and find nothing more definite in regard to 

 these particulars than the name of the State — 

 it may be ' Texas,' or again, the ' Rocky Moun- 

 tains.' The author meets here a condition of 

 things which places him at a disadvantage — by 

 rendering his work incomplete — with the reader 

 or student of biology, a position which might 

 have been avoided by a trifling effort on the 



