Pall.; the two species (aside from the shifting of names) standing in the same relation precisely as heretofore. Had S. arctica Pall. been written down a synonym of S. Pallasii, and S. arctica R. Br. been left intact, some degree of consistency could be urged in behalf of an author who throughout pay's little or no regard to claims of priority. It might be argued that S. arctica R. Br. was so deeply embedded in the science that it could not and ought not to be torn out by the roots, and that it were better, since one of the two names must be suppressed, that the more obscure-even if confessedly the older one-be sacrificed. Any such apology, however, is felt to be out of place when we have a new name given to the old S. arctica Pall., the authority of Pallas trans ferred to a species of which he was entirely ignorant, and Robert Brown left out entirely.'

But we are not obliged to rest our judgment solely upon the characters given, though in the present instance this evidence is in itself conclusive. Not only does the name, S. Pallasii, imply the earlier description by Pallas, but we have Andersson's own admission that he had seen the specimens of Sujef (type of S. arctica Pall!) "in the herbarium of Pallas, inscribed S. arctica," and that these did not differ from hist S. Pallasii, var. diplodictya!

The venerable Dr. Trautvetter, whose special study of arctic willows and whose familiarity with the work done on Salix by Russian botanists, must combine to give his opinion a weight beyond that of Andersson's, writes in a letter: "S. diplodictya differs from S. crassijulis (S. arctica Pall. not R. Br.), only in the leaves green and shining beneath, and it may be questioned if the species is well founded." Here, in a brief sentence, we have the pith and substance of the

distincte reticulato-nervosis,

subtus sericeis,

amenta fæeminea magna bipollicaria, digiti amentis femineis fere bipollicaria, crassius

minimi crassitie

e lateribus ramorum,

longius pedunculata duobus,

tribusve foliis majusculis

culis, lateralibus

"Capsulæ confertæ," Pall., and "amentis densifloris," And.-meaning the samecould not be conveniently arranged opposite each other in the schedule.

Pallas died 1811, twelve years before S. arctica R. Br. (based upon specimens brought home by British explorers) was published.

whole matter. 1, That S. diplodictya is not distinct from S. crassijulis; 2, that S. crassijulis is synonymous with S. arctica Pall. (which is the main point); and finally, 3, the familiar assertion that the S. arctica of Pallas is not the S. arctica of Robert Brown—a statement which can not be made too emphatic, in view of the placid acquiescence, for years past, in the dictum of Andersson to the contrary.

66

It is to regretted that a name grown so familiar as that of S. arctica R. Br. must needs be disturbed; on the other hand, the open fact of the priority of S. arctica Pall. can not be ignored, and as what Sir William J. Hooker was wont to call Mr. Brown's S. arctica" was only sustained by the constant mention of the name of the distinguished author, let us hope that the substitution of this name for the one preoccupied may in a large measure preserve unbroken the old associations.

Rockford, Ill.

The Diatom marshes and Diatom beds of the Yellowstone National Park.

WALTER H. WEED.

It is well known that the minute algæ, to which the name of diatoms has been given, possess, in a remarkable degree, the power of separating silica from solution in the waters in which they live. This action is the more remarkable because the silica is often present in such exceedingly small amounts that an almost inconceivable activity on the part of the plant is required to obtain an adequate supply to form their frustules, while the separation of the silica must itself be referred to some vital force exerted by the plant during its growth. It is this action which gives to this low form of life its importance as a geological agent.

As the Diatomaceæ exist under very diverse and extreme conditions of environment, occurring in the icy waters of polar seas, the heated currents of the tropics, and even in the almost boiling waters of hot springs, they are in consequence the most widely distributed form of life known, and their common occurrence in ponds and ditches is well known to every microscopist. Nevertheless, contemporaneous deposits formed of their remains are usually small in comparison with

Pall. the two species (aside from the shifting of names) standing in the same relation precisely as heretofore. Had S. arctica Pall. been written down a synonym of S. Pallasi, and S. arctica R. Br. been left intact, some degree of consistency could be urged in behalf of an author who throughout pay's little or no regard to claims of priority. It might be argued that S. arctica R. Br. was so deeply embedded in the science that it could not and ought not to be torn out by the roots, and that it were better, since one of the two names must be suppressed, that the more obscure-even if confessedly the older one-be sacrificed. Any such apology, however, is felt to be out of place when we have a new name given to the old S. arctica Pall., the authority of Pallas trans ferred to a species of which he was entirely ignorant, and Robert Brown left out entirely.'

But we are not obliged to rest our judgment solely upon the characters given, though in the present instance this evidence is in itself conclusive. Not only does the name, S. Pallasii, imply the earlier description by Pallas, but we have Andersson's own admission that he had seen the specimens of Sujef (type of S. arctica Pall!) "in the herbarium of Pallas, inscribed S. arctica," and that these did not differ from his S. Pallasii, var. diplodictya!

The venerable Dr. Trautvetter, whose special study of arctic willows and whose familiarity with the work done on Salix by Russian botanists, must combine to give his opinion a weight bevond that of Andersson's, writes in a letter: "S. diplodictya differs from S. crassijulis (S. arctica Pall, not R. Br.), only in the leaves green and shining beneath, and it may be questioned if the species is well founded." Here, in a brief sentence, we have the pith and substance of the

minimi crassitie

S. Pallasii et a. crassijulis And. "Folia supra medium

pollice latioribus,

obovatis,

apice rotundatis,

integerrima,

distincte reticulato-nervosis,

subtus sericeis,

amenta foeminea magna bipollicaria, digiti amentis femineis fere bipollicaria, crassius

culis, lateralibus

"Capsulæ confertæ," Pall., and "amentis densifloris," And.-meaning the samecould not be conveniently arranged opposite each other in the schedule.

Pallas died 1811, twelve years before S. arctica R. Br. (based upon specimens brought home by British explorers) was published.

whole matter. 1. That S. diplodictya is not distinct from 5. crassijulis: 2. that S. crassijuli: is synonymous with 3 tica Pall. (which is the main pointy and finally, 3, the fimiliar assertion that the S. arctica of Pallas : not the S arch of Robert Brown-a statement onion can not be made for emphatic, in view of the placid acq mention, for prats pasty in the dictum of Andersson to the contrary.

..

It is to regretted that a name grown so familliat að fat of S. artica R. Br. met needs be disturbed con hand, the open fact of the priority of is arctica Pall can 226 de toured, and is in [ Hooker mes

the immense beds of Tertiary age, which occur in many parts of the world.

In the prosecution of geological work in the Yellowstone National Park, the writer has found that diatom beds of recent origin cover many square miles in the vicinity of the geyser and hot spring basins. These deposits, which are among the largest fresh water diatom beds of contemporary age known, are still forming by the growth of diatoms in the warm water marshes supplied by the hot spring waters.

These diatom marshes are sure to be remembered by all who may attempt to cross them, for the treacherous surface and apparently bottomless depths of the ooze offer an effectual barrier to any progress in that direction.

Near the Emerald springs at the Upper Geyser Basin of the Firehole river, the most noted geyser region of the park. there is a typical marsh of this character. The waters have in times past encroached upon the neighboring patch of timber, killing the pines (Pinus Murrayana), whose bare. gray trunks stand upright in the ooze or lie scattered about half immersed beneath the waters of the marsh. A subsequent partial recession of the water has left a bare, white strip between bog and wood, on which vegetation has as yet a feeble hold, and the gaunt poles of the dead pines stand in a white powdery soil that is evidently a dried portion of the marsh mud. A large part of this bog is covered with a sparse growth of brackish water plants, and the drier parts are grass grown and form a fairly firm meadow bottom. The greater portion consists, however, of a semi-liquid, greenish gray, dirty looking ooze. Under the microscope this was found to consist of beautiful siliceous tests of various species of diatoms. Samples of this material, which Mr. Francis Wolle has kindly examined for me, were found to contain the following species:

The first species named, Denticula valida, was the most abundant, forming the bulk of the specimen. It may be of interest to note here that this species has been found in the gatherings from the geyser basins of Iceland.

The white pulverulent material at the margin of the bog