374 



SCIENCE. 



[Vol. XX. Na 517 



With regard to Ihe Miocene fossils, especially the Cetacean ver- 

 tebree, settled into the broken surface of the Greensand, I did not 

 enter into detail as to a wider distribution of these remains. It 

 was not necessary for me to open out another series of observa- 

 tions heyond my immediate purpose. Let it suffice to say. how- 

 ever, that these remains are not confined to the surface of the 

 Oreensand, but that other specimens of the same were found by 

 my own efforts at various points heyond this section of the bluffs. 



I cannot admit that "each season presents new phases and un- 

 settled local stratigraphic complications'" in more than a su|er- 

 ficial sense. The body of the promontory is not broken up, 

 although every storm does abstract from or disturb a part of its 

 face. Photographs in my possession show various changes which 

 have been made from time to time in the ends and sides of the 

 beds there exposed, but not a dislocation of the main hody of the 

 ridge. They confirm also the observation that several buttresses 

 ■of the '■ Raritan " resting ui^od the lead-colored clay extend out- 

 ward in original order from the ridge, whde the intervening ones 

 flanking the gullies are built of overthrown strata. 



The so-called faulting is of a type common to clayey and sandy 

 terranes. such as we are familiar with in tl e tide- water region of 

 Maryland, where atmospheric agents, especially frost and thawing, 

 open cracks somewhat parallel to the brow of a bluff. These 

 cracks gape wider and extend deeper as the power of the sun in- 

 creases, and at length cause a down-slide or fall when the beds 

 become weakened by saturation with rain-water. Such fissures 

 ■are also opened more widely and deeply by the dropping into 

 them of coarse sand and pebbles, which spread apart by freezing 

 and thawing. A notable example of this kind occurred to my 

 observation on the projection of a heavy body of massive granite 

 on Jones's branch, near Baltimore, where a fissure caused by 

 freezing and thawing was gradually opened by an influx of sand, 

 but which burst apart with almost explosive force one afternoon 

 in the spring, following a season when numerous quartz pebbles 

 had fallen into the crack from the overlying soil. The same 

 phenomenon may be seen in the broken masses of granite which 

 •occur in places along the shores of Fisher's Island, near New Lon- 

 don, Conn. 



Several years ago, when many of the trees had been cleared 

 from the brow of the cliffs of Potomac clay, along the shores of 

 the Patapsco River, fissuring took place at intervals near the 

 borders of these hills, and downthrows from the front of the bluffs 

 were of common occurrence. In connection with such move- 

 ments, and especially following a season of heavy autumnal rains, 

 large cavities were rent in the cracking clays, some of which were 

 large enough to admit a moderately large boy. 



An example of the Gay-Head type of slipping, crushing, and 

 swelling out, on a somewhat smaller scale, may be seen adjoining 

 Sullivan's Cove, ai the north western end of Round Bay, Severn 

 River, Md., and several of the same features, on a grand scale, 

 may be studied next the face of Maulden's ridge, on the North- 

 east River, Md. 



The type of cutting and downthrow of the bluffs on the Vine- 

 yard Sound side of Gay Head is far more complex and varied than 

 that of the south-west, or Atlantic, side. On the former the diag- 

 onal stroke of a surf from the south-east would cut deeper than 

 the straight forward blow of the Atlantic on the south shore, and 

 accordingly would be more effective in undermining the face of 

 the terrane. The effects of those two methods of erosion are well 

 shown on the opposite sides of this coast. 



"With regard to the aggregation of the non-marine lower portion 

 of this series of formations, it seemsprobable that they were begun 

 in the rocky hollows along the whole Atlantic coast from Maine 

 to Cape Hatteras; that rapid currents carried large accumulations 

 of broken stone and the elements of the crystalline rocks many 

 miles out into a shallow sea, which was later barred out by the 

 thick accumulations of these deposits, that thus a series of almost 

 closed sounds was connected with the border of the continent, and 

 that these sounds, extending in a sinuous north-east line, were 

 the places of deposition of all the beds and strata which we now 

 Tecognize as the Potomac, Albirupean, and the Raritan forma- 

 tions. 



It has been my pleasure to read carefully both of Professor 



Shaler's accounts of Gay Head, and to recognize the many good 

 statements that he has made regarding particular features of the 

 region; but I fail to see that he has given an adequate account of 

 the real structure of the promontory, of its relations to otherparts 

 of the island, or of its relations to the similar deposits in Massa- 

 chusetts, Rhode Island, and Long Island. P. R. Uhlek. 

 Baltimore, Md., Dec. 19. 



The Reticulated Structure of Protoplasm. 



After I had read the proof of the article on the reticulated 

 structure of human red blood-corpuscles published in Science fov 

 Sept. 16. 1892, I received a book recently issued in Paris, and en- 

 titled '-La Cellule Animale, sa Structure et sa Vie, Etude Biolo- 

 gique et Practique, par Joannes Chatin, Professeur adjoint a la 

 Faculte des Sciences de Paris, Charge du Cours d'HistoIogie a la 

 Sorbonne, Menibre de I'Academie de Medicine." In this delight- 

 ful treatise, which brings the knowledge of the animal cell to the 

 present time, there are one or two statements in regard to the 

 structure of protoplasm which I should have liked to quote in 

 the paper mentioned, but as that is now impossible, I have asked 

 the editor kindly to allow me to call attention to the follow- 

 ing: — 



C'est seulement en 188(i, a la suite des recherohesde Heitzmann, 

 de Fromann et surtout des publications de Hanstein, que Ton 

 commence a modifier la conception generale du protoplasma, pour 

 le considerer, non plus comme une masse indifferente, mais comme 

 une substance structuree. 



Cette interpretation recontra une assez vive opposition. II est 

 des esprits scientifiques qui tiennent a demeurer constamment 

 fideles aux principes dont ils se sont inspires des leurs premieres 

 etudes et qu'ils ne consentent que difficilement a abandonner. . . . 



On doit distinguer dans le protoplasma deux parties: Vhyalo- 

 plasraa et \e paraplasma (Fig. 49). 



L'hyaloplasma est une substance fibrillaire, hyaline, refringente, 

 formant un reseau au milieu d'une substance fluide, moins re- 

 fringente, qui est le paraplasma. Qu'on se represente une eponge 

 a travees tres tenues et contractiles, plongee dans une substance 

 visqueuse et granulee qui remplirait ses cavites. Cette com- 

 paraison donne une idee grossiere, mais assez exacte, de la masse 

 proloplasmique prise dans son ensemble. 



Elle parait homogene si les mailles de I'liyaloplasma sont uni- 

 forraes et qu'on fasse usage d'un faible grossissement. C'est ainsi 

 que le protoplasma avait et6 etudie durant longtemps, et Ton 

 s'explique d'autant mieux I'erreur dans laquelle on demeurait a 

 regard de ses parties constitutives, qu'elles ne se distinguent en 

 general qu'apres I'intervention de certains reactifs comme I'acide 

 osmique. Cependent I'histologie zoologique permet de les observer 

 directeraent. et j'ai deja eu ^'occasion de mentionner a cet egard 

 I'exemple des cellules glandulaires de la Testacelle. ■ 



La structure reticulee du protoplasma s'observe dans les cellules 

 amiboides comme dans les Slements a forme d finie; I'etude des 

 globules sanguins des Invertebres (Vers, Crusiaces, etc.), permet 

 de constater aisement ce fait, d'aboi'd revoque en doute par des 

 observateurs qui limitaient leurs recherches aux elements de 

 quelquels animaux superieurs. ALFRED C. Stokes. 



TrentoD, New Jersey. 



Auroral Displays. 



In answer to Professor Swift's inquiry in Science of Dec. 9, I 

 will say that I saw " that memorable spectacle " in the winter of 

 1834 or 5 when " the snow and the sky suddenly assumed," in the 

 evening, •■ a bright crimson red." It is one of the most distinct 

 things in ray remembrance. I was then well along in my "teens," 

 but had not then undertaken very extensive meteorologic observa- 

 tions and records. 



When Dr. Swift speaks of the aurora of July 16 last as "the 

 grandest auroral display of the century," does he take into account 

 the great aurora of August, perhaps, in 1859, when the whole sky 

 was covered with beautifully colored streamers? A fine corona 

 appeared, the display lasted fi-om evening until morning twilight, 

 was repeated less brilliantly during the following night, and with 

 intermediate disturbances of the telegraph lines and of the mag- 



