40 



NATURE 



[July 14, 1910 



at least a small portion of the time of the new commission 

 will be devoted to a subject of such importance. 

 Malvern. Hilderic Friend. 



In some interesting remarks upon this subject (Nature, 

 pp. 427, 4S9), the Rev. Hilderic Friend suggests — and I 

 believe he is correct in assuming for the first time — that 

 the alluvial mud of such a river as the Nile derives its 

 fertility, not from the nature of the sediment itself, as 

 usually supposed, nor entirely from bacteria, but from the 

 multitudinous remains of annelids that live in the mud. 



That there is " need for careful study of the alluvium 

 of rivers from this point of view," and any other, is to 

 be freely admitted. If we except the study of pre- and 

 post-Pleistocene deposits carried out by Mr. Clement Reid, 

 and summarised in his " Origin of the British Flora," 

 there is scarcely another work that can be mentioned deal- 

 ing with the subject. It is true that lately the Geological 

 Survey have become alive to the necessity of introducing 

 details as to the fertility or otherwise of the soils derived 

 from the geological formations surveyed. But these are 

 isolated, and are but the necessary outcome of previous 

 activities of agricultural e.'cperimental stations. But neither 

 have these latter undertaken any systematic study of the 

 character and constituents of river alluvium. The nearest 

 approach to a treatise on the subject is Darwin's " Earth- 

 worms," and his work, whilst dealing with terrestrial 

 forms and their influence in fertilising, renewing, and 

 enriching the soil, strangely enough bears out Mr. Hilderic 

 Friend's suggestion as to the cause of alluvial fertility. 



For without earthworms, what would the soil be? 

 Ergo, without fluviatile annelids, what would the alluvium 

 be — but a sterile accumulation of sand? Here we may add 

 that where worms are too plentiful on land bad results 

 follow, so too we may assume, accepting the worm- 

 fertilising theory as correct, that an excess of annelids tends 

 to cause, as on land, putrefaction, as may be illustrated 

 by the case of ponds overstocked with blood-worms, 

 causing the appearance of blood, which was a fruitful 

 source of superstition in former days, notably at Garendon 

 in this district. 



But apart from theoretical considerations, based on the 

 hypothesis that Tubitex and other annelids do tend to 

 increase fertility, we may attempt to draw an analogy with 

 former^ conditions, and so to some extent corroborate Mr. 

 Friend's very probable theory. 



All who have made any study of the palaeontologv of 

 the Trias (referring here specially to Britain) are familiar 

 with the extreme barrenness of great thicknesses of both 

 Lower and Upper Keuper relieved alone by certain limited 

 horizons at which a definite flora and fauna is to be met 

 with. 



It has been assumed, and there is apparently no great 

 reason^ against this on a purely faunistic basis, that the 

 Trias is a desert formation ; but on other grounds, and also 

 from a study of the flora and fauna, I have come to the 

 conclusion (during a study of the Midland Trias, in which I 

 am aided by a Government grant from the Roval Society) 

 that the whole of the Triassic formation is a delta forma- 

 tion, in other words, that from the Bunter (first suggested 

 to be a delta deposit by Prof. Bonney) upwards conditions 

 similar to those in the Nile area prevailed during Triassic 

 times, and were responsible for its formation. Locally, 

 wind acted on rocks, but formed no deposit. 



Now it is a remarkable fact that in the deposits in the 

 British Keuper, in which alone plant-remains have so far 

 been discovered, or where carbonaceous deposits occur, 

 that a common associate of the plant-remains is a form of 

 track or casting which has usually been ascribed to 

 annelids or Crustacea ; and we must not overlook the fact 

 that annelids alone are not the predominating component 

 of the fauna of alluvial tracts, but Protozoa in their 

 myriads, occasionally sponges, Crustacea (minute and 

 large), insects, scorpions, and molluscs form a large pro- 

 portion of the bulk of alluvial deposits. Of these, annelids 

 and Crustacea are most likely to be preserved, and are 

 most often discovered in the rocks. So that it seems that 

 only where annelid life in Triassic times was abundant 

 w.-js plant-life in evidence, just as now only where the 

 Nile is alluvial does it yield productive results, due, appar- 

 ently, to the same cause. The analogy I have drawn 



NO. 2124, VOL. 84] 



strengthens Mr. Friend's theory, and, moreover, if the 

 worms be found to be actually conducive to fertility (by 

 experiment or otherwise), my case for the delta-origin of 

 the Trias will receive additional confirmation. 



It would seem to us that no more fitting study could 

 be made by the lake surveys that are now going on in 

 different; parts of the kingdom than the very probable 

 connection between worms and alluvium, for it seems that 

 Mr. Friend has more or less proved his case without much 

 need for argument. This affords another instance of the 

 utility of beings hitherto supposed to have no useful part 

 to play in the history of time or things. 



July 2. A. R. HoRwooD. 



A Singular Mammal called " Orocoma." 



In a letter of the Jesuit Father Cat at Buenos Aires, 

 dated May i8, 1729 (" Lettres .ditiantes," ^d. Lyon, 1819, 

 torn, v., p. 466), the following passage occurs : — 



" Outre ces animau.x, il en est un qui m'a paru fort 

 singulier : c'est celui que les Moxes appellent orocoma 

 [or ocorome, according to the " .'\br^g^ d'une Relation 

 espagnole," in the same tome, p. 66]. II a le poll roux, 

 le museau pointu, et les dents larges et tranchantes. 

 Lorsque cet animal, qui est de la grandeur d'un gros 

 chien, aper^oit un Indien arm4, il prend aussitot la fuite ; 

 mais s'il le volt sans armes, il I'attaque, le renverse par 

 terre, le foule a plusieurs reprises, et quand il le croit 

 m.ort, il le couvre de feuilles et de branches d'arbres, et 

 se retire. L'Indien, qui connoit I'instinct de cette bete, 

 se live dis qu'elle a disparu, et cherche son salut dans la 

 fuite, ou monte sur un arbre, d'ou il considire i loisir 

 tout ce qui se passe. L'orocomo ne tarde pas A revenir 

 accompagn^ d'un tigre qu'il semble avoir invito d venir 

 partager sa proie ; mais ne la trouvant plus, il pousse des 

 hurlemens ^pouvantables, regarde son compagnon d'un air 

 triste et di5sol(^, et semble lui t^moigner le regret qu'il a 

 de lui avoir fait faire un voyage inutile." 



In asking what mammalian species this " orocoma " is, 

 and whether there is the slightest foundation for this 

 story, I fully know I am showing my great ignorance. 

 I hope the Editor and his readers will forgive me, taking 

 into account the entire absence of a scientific reference 

 library in this part. Kumagusu Min.m<.\ta. 



Tanabe, Kii, Japan, June 15. 



Pwdre Ser. 



When a boy, at the latter end of the 'thirties of last 

 century. I was told by a well-known man of the name of 

 West — lock-keeper on the river Witham at Lincoln — that 

 he had seen a star fall on the south common there, where 

 he had a cow grazing, and that, on going up to it, he 

 found nothing but a lump of jelly. At this distance of 

 time I cannot recall all he said, but I remember he 

 described the object as shining and as about the size of a 

 plate. I have no recollection of his calling it luminous. 



Up to this time I have always thought my informant 

 was under an illusion, but, after Mr. McKenny Hughes's 

 article, there seems to be something more than I was 

 aware of in the account he gave me. 



F. M. Burton. 



Highfield, Gainsborough, July 2. 



Curve Tracing and Cuive Analysis. 



I HAVE unwittingly done an Injustice to Mr. R. H. 

 Duncan's book on " Practical Curve Tracing " (vol. 

 Ixxxiii., p. 461). I judged by the review of it in N.ature 

 of June 9 that it deals only with the subject indicated by 

 its title. After writing to you regretting that no author 

 deals with practical curve analysis, I bought Mr. Duncan's 

 book, and find that, after describing each class of curve 

 and how to trace it, he gives clear directions for reversing 

 the process and deducing a formula from a given curve. 

 So far as it goes, the book excellently meets the want 

 which I expressed, and my only regret is that the author 

 has not developed the subject a little further. 



A. P. Trotter. 



London, July 5. 



