134 



NATURE 



{June 13, 1872 



There are also useful practical papers of instructions for herbo- 

 rising, for collecting micro-lepidoptera, and for preparing birds' 

 eggs ; as well as a large number of interesting paragraphs of 

 information under the heads of tlie natural sciences. 



The yjiirnal of the Fraiikiii Institute for May contains a good 

 drawing of Danks's patent puddling furnace, and a large num- 

 ber of paragraphs under the head "Items and Novelties." Tlie 

 substantial articles include a continuation of Prof. Nourse's paper 

 on inter-occanic communication across Central America ; Mr. 

 John Warner on the diamond rock drill ; Mr. C. Van Bruol on 

 a new modification of the Holtz machine, and a list of auroral 

 displays daring February at a number of stations in the United 

 States ; and tlie continuation of various other papers commenced 

 in the preceding numbers. 



The number of the Transactions of the Linneau Society just 

 published, vol. xxix. part I, contains the commencement of 

 Colonel Grant's Botany of the .Speke and Grant Expedition, in- 

 cluding an enumeration of the plants collected during the journey 

 of the late Captain J. H. .Speke and Captain J. A. Grant from 

 Zanzibar to Egypt in 1860-63. The determinations and descrip- 

 tions of the species are by Prof Oliver, Mr. J. G. Baker, and 

 other botanists connected with the Kew Herbarium ; while 

 Colonel Grant writes an introductory preface, alphabetical list of 

 native names, and notes. It is prefaced by a good map of the 

 whole of the journey ; and illustrated by thirty-seven drawings 

 on stone of new or remarkable species. The total number in the 

 whole paper will be loo. 



SOCIETIES AND ACADEMIES 



London 



Geological Society, May 22. — Prof. Morris, vice-president, 

 in the chair. The following communications were read : — i. A 

 communication from the Right Hon. Earl Granville, inclosing 

 a report from H. M. Minister at Rome, relating to the recent 

 eruption of Vesuvius. 2. "On the Pliosphatic Nodules of the 

 Cretaceous Rock of Cambridgeshire," by the Rev. O. Fisher, 

 M.A., F.G. S. This paper contained an attempt to e.\plain the 

 origin of the phosphatic nodules which lie in a thin bed at the 

 base of the Chalk in Cambridgeshire, and are largely extracted 

 by washing the stratum for the purpose of making superphos- 

 phate of lime. Two hundred and seventy tons per acre, at the 

 rate of fifty shillings a ton, represents the valuable yield of the 

 deposit, which is followed to the depth of about iS feet. Tlie 

 nodules and other fossils of the bed are chiefly derivative, form- 

 ing a concentrated accumulation from a deposit belonging to the 

 Lower Cretaceous period. Some of the fossils are, ho^^•cver, 

 believed to be indigenous to the deposit. Plicatula: are attached 

 to all the derivative fossils and nodules, and the sharp, broken 

 surfaces of the latter, with Plicatiilis on them, show that they 

 were mineralised before they were deposited in their preseiit 

 gisentent. The green grains of chlorite have been drifted into 

 patches. Certain calcareous organisms are preserved, but many 

 genera of molluscs only occur as casts in phosphate of lime. 

 The phosphatic matter has been determined in its deposition by 

 (7«//«i7/ substances. There are two chief varieties of the " or- 

 dinary " nodules. Tlie first are amorphous, or else finger- 

 shaped ; the second formed like a long cake rolled partially or 

 wholly upon a stick. The surface of these two kinds of nodules 

 is coriaceous and wrinkled, and they usually show marks of at- 

 tachment to some foreign body. Certain species, clearly zoo- 

 phytes, are converted into phosphatic nodules, and, when sections 

 are made of these, they are found to show under the microscope 

 structures and spicula; allied to those of Alcyonaria. Slices of 

 the common nodules show similar spicular,^and occasionally 

 reticular structure. When casts in plaster are made from Alcyo- 

 niiim Jigitatnin, and coloured to resemble the nodules, the 

 similarity in general form and structure of surface is very striking. 

 The phosphate was probably segregated by the animal matter 

 from its solution in water charged with carbonic acid, which is a 

 known solvent of the phosphate ; an analysis of the matrix has 

 proved that phosphate of lime is appreciably present in it. The 

 author doubted the derivation of the nodules from the denudation 

 of the subjacent Gault, and exhibited a collection of these to 

 show that they were distinguished by more stunted growth. 

 The deposit was on the whole considersd to represent the thin 

 band with similar fossils at the base of the Chloritic Marl, as 

 seen in the West of England, in which district it is underlain by 



the true arenaceous Greensand. The absence of the true Green- 

 sand was attributed to the intervention of the old paleozoic axis 

 of the London area ; and it was finally suggested that a similar 

 axis might si retch from Leicestershire to Harwich, causing the 

 change in character of the Lower Cretaceous beds between Cam- 

 bridgeshire and Norfolk.- 3. " Some observations on the Upper 

 Greensand formation of Cambridge," by Mr. W. Johnstone SoUas. 

 The Greensand Formation consists around Cambridge of a Chalk 

 marl containing harder portions of a different nature disseminated 

 throughout it, these are separated from the Chalk Marl by levi- 

 gation, and sorted by sifting into larger bodies, consisting almost 

 entirely of the so-called "coprolites," and smaller bodies — the 

 so-called " Greensand." The author gave a general account of 

 his conclusions regarding the "coprolites," reserving details for 

 a future communication. Of all the facts the most obvious is 

 the connection between presence cf " coprolite" and former 

 existence of organic matter; when coprolite is fraud incrust- 

 ing a bone or other fossil, it is precisely on those parts where 

 animal matter adhered most abundantly. Instances were cited, 

 as in Falicocoiystcs, where the absence of animal matter on 

 the b.ick cf the carapace is marked by an absence of phos- 

 phatic incrustation ; while the sternal side, where animal 

 matter could easily escape, is often altogether embedded in 

 " coprolite." Coprolites are the fossilisation of organic matter 

 derived from very various sources. In many cases they owe 

 their origin to sponges, almost certainly so in the case of 

 cylindrical coprolites perforated by a cylindrical cavity, now 

 filled up with Chalk Marl ; other forms have an allied origin. 

 Thus coprolites are the flints of the Gault. The Greensand 

 is a mixture of calcareous, silicious, and dark-coloured grains of 

 uncertain chemical composition. The calcareous grains consist 

 of sponge spicules, minute shells, fragments and prisms of shell 

 substance, bivalve entomostraca, microscopic corals, minute 

 echinoderm species, polyzoa, and foraminifera. A list was given 

 of the foraminifera, the abundant occurrence of Lagma here being 

 particularly noticed, as, with the exception of L. apiculata, men- 

 tioned by Reuss, the genus had not before been noticed below 

 the Maestricht Chalk. The silicious grains consist of firagments 

 of various rocks, some of volcanic origin. The dark coloured 

 grains are coprolitic debris and true green grains. The green 

 grains are almost all casts of foraminifera, derived chiefly from 

 Bnlimina ; others are derived from Litnola, Rotalina, Globi- 

 gcrina, and other forms. Some green grains of exactly the 

 same nature had been found by the author in the silicious sand of 

 Blackdown. — Prof. Phillips was glad that his casual remark had 

 produced such satisfactory results as the paper he had heard. It was 

 satisfactory to find that the bulk of the phosphatic nodules exhi- 

 bited such marked traces of an organic origin. Though he had to 

 some extent been prepared for this, it appeared thatthe viewmight 

 be extended much further than would at first sight have been anti- 

 cipated. He drew an analogy between the preservation of the 

 forms of sponges in their silicified fossils with that of the soft 

 organic bodies in the Greensand by phosphatic matter. In each 

 c:ise the surrounding water contributed a large amount of either 

 fiint or phosphate of lime, which was segregated and accumulated 

 round certain centres or nuclei of organic bodies. — Prof. Ramsay 

 inquired from what sources the abundance of phosphatic matter 

 requisite for the production of these fossils could have been 

 derived. In such thin strata, which seemed to indicate a transi- 

 tion from a land to a marine surface, it was a matter of great 

 difficulty to his mind to account for so great an abundance of 

 phosphatic matter. — Jlr. Godwin-Austen remarked that phos- 

 phoric acid was largely present in sea water, and instanced the 

 present seas, where, as on the Newfoundland banks, fish existed 

 in enormous quantities, and no doubt also phosphatic matter. 

 The Cambridge beds, though so rich, were by no means unique 

 of their kind. He referred to a paper communicated some years 

 ago to the Society by Mr. Payne, as affording many interesting 

 particulars with regard to such beds. He considered that much 

 of the phos|3hate attaching to decaying animal matter might have 

 b.'en derived from comminuted excrementitious deposits floating 

 in the water. — The Rev. T. G. Bonney remembered a fact 

 quoted by the late Dr. Mantell as to the large quantities of dead 

 MoUusca which had been observed floating down some of the 

 American rivers, and which had been regarded as a plentiful 

 source of phosplia'ic matter. .Small fishes might also have fur- 

 nished a considerable quantity, and their value as manure was 

 recognised at the present day. With regard to the nodules being 

 Alcyonaria or sponges, he observed that what spicules he had 

 seen appeared more like those of sponges. He agreed with Mr, 



