zy- 



SCIENCE. 



[Vol. XX. No. 514 



true, then the reticulation within the reii blood-corpuscli^s is a 

 normal structure ; if not true, then the whole body of histological 

 work which has been accepted as coiTect must be doubted and be 

 revised, because about the first thing Ih • bistologist does with his 

 specimen is to plunge it into a solution of ooiassium bichromate. 

 Indeed, he does more, for he not rarely uses Milller's fluid, which 

 is a mixed solution of potassium bichromate and of sodium sul- 

 phate. There seem to be two horns to the dilemma, and the mi- 

 crosoopist that seizes either is likely to he gored by the other. 



LETTEES TO THE EDITOR. 



#», Correspondents are requested to be as brief as possible. The ; 

 is in all cases required as proof of good faith. 



On request in advance, one hundred copies of the number containing his 

 communication will he furnished free to any correspondent. 



The editor will be glad to publish any qupries consonant with the charactfr 

 of the journal. 



The Cretaceous at Gay Head, Martha's Vineyard. 



In his article on "Gay Head,'' published in this journal of Sept. 

 23, and since supplemented in the Tran-actions of the Maryland 

 Academy of Sciences (pp 3o4-il3), my friend Professor Uhler 

 furnishes a valuable contribution to the geological literature on 

 that peculiarly interesting promontory, through applying to the 

 task of unravelling the complicated structure of the 'Vineyard 

 series the knowledge and experience gained in his painstaking 

 and excellent studies of the Lower Cretaceous terranes between 

 New York Bay and the James River. Professor Uhler is the first, 

 in print, to apply, in the interpretation of the di-^turbed strata in 

 the western portion of Martha's Vineyard, the general principles 

 ■which he was first to discover in the mode of disposition of the 

 same series in the Middle Atlantic States. To one somewhat 

 familiar with the Middle and Lower Cretaceous of New Jersey 

 and Maryland, the homologies forcibly indicated in the "Vineyard 

 series are full of fascinating interest. 



While agreeing with Professor Uhler as to the general structure 

 of the original Cretaceous series in Martha's Vineyard, i.e., in the 

 existence of a lower portion, essentially clays, succeeded by de- 

 posits of sands, lignitic clays, often somewhat laminated, and 

 alternate clays and sands, — the observations of Professor Shaler 

 and those of us who have viewed the cliffs for several successive 

 seasons have taught the fallibility of indulging in a detailed cor- 

 relation of the entire section as exposed during a single summer. 

 Each season prtsents new phases and unsettled local stratigrapbic 

 complications, revealed by the winter's storms, as may be noted 

 by consulting Professor Shaler's very valuable memoir, published 

 in the Seventh Annual Report of the U. S. Geological Survey 

 (pp. 297-363, 12 plates), the same author's paper in tbe Bulletin 

 of the Geological Society of America (Vol. I., pp. 443-452, pi ix.) 

 (neither article is mentioned by Professor Uhler), or in my notes 

 made during 1889, 1890, and 189L It seems to me, therefore, that 

 Professor Uhler has been a little confident and hasty in naming 

 up the various terranes at Gay Head. In offering some friendly 

 comments on his conclusions, it is not my purpose to discuss sev- 

 eral important questions, such as whether the island has been 

 submerged "five times" or only three, or matters of nomenclature, 

 as, for example, whether the underlying clay series should be 

 called "Potomac" or Araboy, or the more arenaceous portion 

 designated as " Raritan," " Alblrupean,'' etc. These questions, as 

 well as those concerning unconformability and the order and re- 

 lations of the various members of the lower half of the Cretaceous 

 in this region, as well as in other Atlantic coast States will, I 

 trust, soon be considered in full by Professor Lester F. "Ward of 

 the U. S Geological Survey, who has made them the subject of 

 special study, and who is far more competent to discuss them than 

 the present writer. The folding, crushing, faulting, and disloca- 

 tions at Gay Head make a unique example in the Cretaceous and 

 Tertiary of the eastern United States. It is difiicult to account 

 for the surprising altitudes of the clays and lignites, as well as 

 extensive elevation and pre- Tertiary erosion, with no other agency 

 than pressure and the encroachment of the sea. In fact, the 

 strata are so disturbed, eroded, mingled with, and masked by, post- 

 Cretaceous deposits that it is, in my opinion, hazardous, in many 

 portions of the section, to attempt more than the application of 



the general principle of distinction between the lower portion, 

 with more massive clays, and the upper part, embracing various- 

 ly arranged clays and sands 



The greensand toward the north end of the section is much con- 

 torted, as described, but my own excavations in search of fossils 

 fail to corroborate my friend's hypothesis that the Tertiary 

 fossils " have settled into the broken surface," the interior of the 

 marl being, in his judgment, equivalent to the lower marl of New 

 Jersey, and carrying Cretaceous fossils only. If such is the ex- 

 planation of the occurrence of Tertiary fossils on the face of the 

 greenstind, it is remarkable that they have not, likewise, settled 

 into the broken surface of the clays and sands on either side. A 

 similar marl was seen well exposed in the season of 1889 at one or 

 two points towards the eastern end of the Weyquosque cliffs Id 

 Chilmark, where at one place the materials in the margin of the' 

 terrane appear to have been beautifully sorted in Pleistocene or 

 post Pleistocene time. 



With Professor Uhler I agree that the greater portion of the 

 strata below the "ossiferous" conglomerate, which appears to be 

 Miocene, is probably Cretaceous in age. As to whether the more 

 massive clays are equivalent to tbe plastic clays of the Potomac 

 in the Maryland region, I shall not question in this place, merely- 

 mentioning the occurrence of Dicotyledonous remains among the 

 dark clays at high-tide level near that portion of the section 

 which I understand my friend to pronounce Potomac. It is pos- 

 sible, of course, that this terrane had slipped down from the upper 

 part of the cliff, and may be regarded by Professor Uhler as 

 " Riritan." The latter name suggests the remark, that, while re- 

 ferring the lower clays to the " Potomac," and explaining that the 

 superimposed series, called " Raritan," is equivalent to the upper 

 part of his " Alblrupean," Professor Uhler makes no mention of 

 the presence or absence of the rest of, or the lower portion of, the 

 Alblrupean, theoretically intervening between the Raritan and 

 Potomac as defined by him. 



So far as I now know, my paper on •' Cretaceous Plants from 

 Martha's Vineyard,'" read at the December meeting of the Geo- 

 logical Society in 1839,' was the first in which the opinion was 

 expressed, or evidence adduced to show that a part, at least, of 

 the Vineyard series represents an eastward extension of the Am- 

 boy clays to tbe southward of New England. The opinion ex- 

 pressed by Dr. Newherry, when delivering his judgment on my 

 drawings, that " there can be no doubt that they represent the 

 flora of the Amboy clays," and his view that these clays passed 

 through the entire length of Long Island, have, I think, been 

 fully justified. During the following summer, 1890, evidence was 

 collected which proved the correctness of those views regarding- 

 the Gay Head region, while my unpublished notes, made the same 

 season, indicate the extengion of the Amboy clays in place as far 

 east as Northport and Fresh Ponds in Long Island, while material 

 probably derived from that series, when not in place, was observed 

 at numerous points, among which are Wyandance, Farmingdale, 

 possibly near Riverhead, and in Gardiner's Island. I anticipate 

 that a careful search among the Pleistocene material between the 

 Firehole and Montauk Point will reveal Amboy elements showing 

 a continuance eastward to the Cretaceo'js material observed by 

 myself in the north-east and south bluffs of Block Island. Oa 

 Martha's Vineyard the Amboy clays may be seen in place at sev- 

 eral points in the vicinity of Peaked Hill, while its material, per- 

 haps re-deposited, may be traced to Lambert's Cove, or farther. 

 Concretions with Amboy plants have been collected on the shore 

 of Lagoon Pond, above Vineyard Haven, while Professor Thomas 

 Battey of Providence has sent me similar specimens from East 

 Chop and Cottage City, on the east coast, showing the probable 

 extension, in past if not in present, of that important series of 

 clays and sands as far, at least, as the eastern border of the 

 island. 



The greater identity of the Amboy (Middle or Lower- Middle- 

 Cretaceous) flora with that of the Lower Atane beds of Green- 

 land, instead of with the Dakota group of the United States, i& 

 remarkable ^ and strongly impels one to search for other evidence 



1 Abstract, Bull. G. S. A., I., pp. 554, 555 ; Printed in tuU In A. J. S., xxxix.„ 

 1890, pp. 93-101, pi. 11. 



» See A. J. S., I.e., p. 99, and Newberry's remarks, BulL G. S. A., I., p. 555. 



