30 



HARDWICKE'S SCIENCE-GOSSir. 



developed into a small moth, which, he says, " are 

 very pretty objects to behold; the wings, which are 

 four in number, being while, sprinkled all over with 

 black spots ; and on examining them with the micro- 

 scope I found that this whiteness proceeded from 

 the white feathers on the wings, and that the black 

 spots were caused by other feathers which were 

 black on the edges. Although I examined some 

 thousands of these feathers, they were all so dif- 

 ferently formed that I canuot say I saw two exactly 

 alike. All of them, although so very minute, have 

 quills like the feathers of birds, by which they are 

 fixed or rooted in the membrane that forms the 

 wing, and so completely cover it that it canuot be 

 seen." 



Here Leuweeuhoek's microscope played him 

 false or his imagination misled him, for as we now 

 know, the butterfly or moth scales exhibit a totally 

 different structure to the feathers of birds. The 

 figures of these scales represent them as having a 

 quill to which barbs are attached precisely as they 

 occur in the feathers of humming-birds. 



The great Dutchman concludes this essay with 

 the following remarks : — " Can any man in his sober 

 senses imagine that this moth, of which I have given 

 the description, which is fitly provided by nature 

 with the means to propagate its species, furnished 

 with eyes exquisitely formed, with horns, with tufts 

 of feathers on its head, with wings covered with 

 such multitudes of feathers all of different shapes, 

 and these exactly covering the wings in every part — 

 can this mo'h, I say, adorned with so many beauties, 

 be produced from corruption ? For, in a word, in 

 this little creature, contemptible as it seems to us, 

 there shines forth so much perfection and skill in 

 the formation as to exceed what we observe in 

 larger animals." 



{To be continued?) 



THE ORIGIN OF THE GREENSAND. 



<< * * * n ow ^ it i s not a fact that greensands of the Cre- 

 taceous epoch are always composed of foraminiferal casts, it 

 is time that the statement of Ehrenberg, endorsed so unre- 

 servedly by Carpenter, should be challenged. "--S. A.Stewart, 

 in Science-Gossip fur Nov., 1875, p. 243. 



rpHE author of the note on " Greensand and its 

 ■*■ Origin," from which the above sentence is 

 extracted, severely censures Dr. Carpenter for 

 accepting the statement that the greensand grains, 

 so constantly met with at the base of the Upper 

 Cretaceous series, are for the most part internal 

 casts of Foraminiuifera in glauconite. 



Now I have no doubt that Dr. Carpenter can 

 very well defend himself, and can give, as indeed he 

 has elsewhere given, very excellent reasons for so 

 unreservedly endorsing Ehrenberg's observation; 

 but as he may not think it worth his while to notice 

 the errors and assumptions visible in Mr. Stewart's 



paper, I beg leave to offer a few observations on the 

 subject ; for as it is a fact that some greensands do 

 mainly consist of foraminiferal casts, the general 

 denial thereof by Mr. Stewart should not pass 

 unchallenged. 



In the first place I think Mr. Stewart has been 

 misled by the expression used by Dr. Carpenter in 

 the particular paper he quotes, viz., " the greensand 

 deposit of the Cretaceous epoch." It is indeed 

 rather a loose statement, since greensand beds 

 occur at many horizons in the series, not at one 

 only, as this might be understood to mean ; but 

 any one who has read Dr. Carpenter's other papers 

 on the subject would know that he is, of course, 

 fully aware of this well-known fact. 



If Mr. Stewart's argument were that all green- 

 sands have not yet been proved to have a forami- 

 niferal origin, and consequently that we should be 

 cautious in taking for granted that they have all 

 been formed in the same way, there would be some 

 reason in it ; but no such discretion is to be found 

 in his communication; on the contrary, he denies 

 the fact in toto, and says : " The assumption that the 

 greensand is formed of casts of Foraminifera should 

 be rejected for the following reasons : — 

 " 1st. Foraminiferal shells do occur plentifully and 

 uninjured in the English greensand ; ergo, 

 there is no cause for assuming the wholesale 

 destruction of calcareous shells in that epoch. 

 "2nd. Calcareous tests of mollusca have re- 

 mained ; casts are rare in the greensand. 

 " 3rd and conclusive. The grains of glauconite in 

 the Irish greensand, when examined with the 

 microscope, show no real resemblance to 

 Foraminifera." 

 My first criticism on these objections is that, sup. 

 posing the statements they contain to be true, they 

 are apparently all founded on the assumption that 

 if certain fossil organisms do not exist in one 

 locality, there/ore they cannot exist in any .other 

 locality ; and I submit that such logic is hardly 

 defensible. 



With regard to the first of these arguments, 

 Mr. Stewart is quite correct in stating the existence 

 of calcareous shells in the Cambridge greensand* 

 but he has apparently overlooked the published fact 

 that glauconitic casts of the same also occur in great 

 abundance. For this I may refer him to papers by 

 Mr. W. J. Sollas, in the Quart. Journ. Geol. Soc, 

 xxviii. p. 397, and in the Geol. Ma//., vol. x. From 

 the former 1 extract the following remarks as being 

 both explanatory and conclusive. 



"From the resemblance of most of the green 

 grains to the Foraminifera found with them, from 

 their rough parallelism in size, from the appearance 

 of many of the grains when sections are made of 

 them, and from the occurrence of glauconite casts 

 in the interior of the original Foraminifera, we 

 must attribute to the green grains a foraminiferal 



